Merge 3eb8d92028 into 6a392fdb0f

Remove match and therefore dependency on Python 3.10

Examples/Echo.py

@@ -5,7 +5,6 @@
 # of the packet.                                         #
 ##########################################################
 
-import os
 import argparse
 import RNS
 
@@ -28,19 +27,8 @@ def server(configpath):
     # We must first initialise Reticulum
     reticulum = RNS.Reticulum(configpath)
     
-    # Load identity from file if it exist or randomley create
-    if configpath:
-        ifilepath = "%s/storage/identitiesy/%s" % (configpath,APP_NAME)
-    else:
-        ifilepath = "%s/storage/identities/%s" % (RNS.Reticulum.configdir,APP_NAME)
-    if os.path.exists(ifilepath):
-        # Load identity from file
-        server_identity = RNS.Identity.from_file(ifilepath)
-        RNS.log("loaded identity from file: "+ifilepath, RNS.LOG_VERBOSE)
-    else:
-        # Randomly create a new identity for our echo example
-        server_identity = RNS.Identity()
-        RNS.log("created new identity", RNS.LOG_VERBOSE)
+    # Randomly create a new identity for our echo server
+    server_identity = RNS.Identity()
 
     # We create a destination that clients can query. We want
     # to be able to verify echo replies to our clients, so we

Examples/Link.py

@@ -28,8 +28,8 @@ def server(configpath):
     # We must first initialise Reticulum
     reticulum = RNS.Reticulum(configpath)
     
+    # Randomly create a new identity for our link example
     server_identity = RNS.Identity()
-    RNS.log("created new identity", RNS.LOG_VERBOSE)
 
     # We create a destination that clients can connect to. We
     # want clients to create links to this destination, so we
@@ -58,7 +58,7 @@ def server_loop(destination):
         " running, waiting for a connection."
     )
 
-    RNS.log("Hit enter to manually send an announce (Ctrl-C or \"quit\" to quit)")
+    RNS.log("Hit enter to manually send an announce (Ctrl-C to quit)")
 
     # We enter a loop that runs until the users exits.
     # If the user hits enter, we will announce our server
@@ -68,12 +68,6 @@ def server_loop(destination):
         entered = input()
         destination.announce()
         RNS.log("Sent announce from "+RNS.prettyhexrep(destination.hash))
-        if entered == "quit":
-            if latest_client_link:
-                latest_client_link.teardown()
-            break
-    print("")
-    exit()
 
 # When a client establishes a link to our server
 # destination, this function will be called with

Examples/Ratchets.py

@@ -0,0 +1,343 @@
+##########################################################
+# This RNS example demonstrates a simple client/server   #
+# echo utility that uses ratchets to rotate encryption   #
+# keys everytime an announce is sent.                    #
+##########################################################
+
+import argparse
+import RNS
+
+# Let's define an app name. We'll use this for all
+# destinations we create. Since this echo example
+# is part of a range of example utilities, we'll put
+# them all within the app namespace "example_utilities"
+APP_NAME = "example_utilities"
+
+
+##########################################################
+#### Server Part #########################################
+##########################################################
+
+# This initialisation is executed when the users chooses
+# to run as a server
+def server(configpath):
+    global reticulum
+
+    # We must first initialise Reticulum
+    reticulum = RNS.Reticulum(configpath)
+
+    # TODO: Remove
+    RNS.loglevel = RNS.LOG_DEBUG
+    
+    # Randomly create a new identity for our echo server
+    server_identity = RNS.Identity()
+
+    # We create a destination that clients can query. We want
+    # to be able to verify echo replies to our clients, so we
+    # create a "single" destination that can receive encrypted
+    # messages. This way the client can send a request and be
+    # certain that no-one else than this destination was able
+    # to read it. 
+    echo_destination = RNS.Destination(
+        server_identity,
+        RNS.Destination.IN,
+        RNS.Destination.SINGLE,
+        APP_NAME,
+        "ratchet",
+        "echo",
+        "request"
+    )
+
+    # Enable ratchets on the destination by providing a file
+    # path to store ratchets. In this example, we will just
+    # use a temporary file, but in real-world applications,
+    # it's extremely important to keep this file secure, since
+    # it contains encryption keys for the destination.
+    destination_hexhash = RNS.hexrep(echo_destination.hash, delimit=False)
+    echo_destination.enable_ratchets(f"/tmp/{destination_hexhash}.ratchets")
+
+    # We configure the destination to automatically prove all
+    # packets addressed to it. By doing this, RNS will automatically
+    # generate a proof for each incoming packet and transmit it
+    # back to the sender of that packet.
+    echo_destination.set_proof_strategy(RNS.Destination.PROVE_ALL)
+    
+    # Tell the destination which function in our program to
+    # run when a packet is received. We do this so we can
+    # print a log message when the server receives a request
+    echo_destination.set_packet_callback(server_callback)
+
+    # Everything's ready!
+    # Let's Wait for client requests or user input
+    announceLoop(echo_destination)
+
+
+def announceLoop(destination):
+    # Let the user know that everything is ready
+    RNS.log(
+        "Ratcheted echo server "+
+        RNS.prettyhexrep(destination.hash)+
+        " running, hit enter to manually send an announce (Ctrl-C to quit)"
+    )
+
+    # We enter a loop that runs until the users exits.
+    # If the user hits enter, we will announce our server
+    # destination on the network, which will let clients
+    # know how to create messages directed towards it.
+    while True:
+        entered = input()
+        destination.announce()
+        RNS.log("Sent announce from "+RNS.prettyhexrep(destination.hash))
+
+
+def server_callback(message, packet):
+    global reticulum
+    
+    # Tell the user that we received an echo request, and
+    # that we are going to send a reply to the requester.
+    # Sending the proof is handled automatically, since we
+    # set up the destination to prove all incoming packets.
+
+    reception_stats = ""
+    if reticulum.is_connected_to_shared_instance:
+        reception_rssi = reticulum.get_packet_rssi(packet.packet_hash)
+        reception_snr  = reticulum.get_packet_snr(packet.packet_hash)
+
+        if reception_rssi != None:
+            reception_stats += " [RSSI "+str(reception_rssi)+" dBm]"
+        
+        if reception_snr != None:
+            reception_stats += " [SNR "+str(reception_snr)+" dBm]"
+
+    else:
+        if packet.rssi != None:
+            reception_stats += " [RSSI "+str(packet.rssi)+" dBm]"
+        
+        if packet.snr != None:
+            reception_stats += " [SNR "+str(packet.snr)+" dB]"
+
+    RNS.log("Received packet from echo client, proof sent"+reception_stats)
+
+
+##########################################################
+#### Client Part #########################################
+##########################################################
+
+# This initialisation is executed when the users chooses
+# to run as a client
+def client(destination_hexhash, configpath, timeout=None):
+    global reticulum
+    
+    # We need a binary representation of the destination
+    # hash that was entered on the command line
+    try:
+        dest_len = (RNS.Reticulum.TRUNCATED_HASHLENGTH//8)*2
+        if len(destination_hexhash) != dest_len:
+            raise ValueError(
+                "Destination length is invalid, must be {hex} hexadecimal characters ({byte} bytes).".format(hex=dest_len, byte=dest_len//2)
+            )
+
+        destination_hash = bytes.fromhex(destination_hexhash)
+    except Exception as e:
+        RNS.log("Invalid destination entered. Check your input!")
+        RNS.log(str(e)+"\n")
+        exit()
+
+    # We must first initialise Reticulum
+    reticulum = RNS.Reticulum(configpath)
+
+    # We override the loglevel to provide feedback when
+    # an announce is received
+    if RNS.loglevel < RNS.LOG_INFO:
+        RNS.loglevel = RNS.LOG_INFO
+
+    # Tell the user that the client is ready!
+    RNS.log(
+        "Echo client ready, hit enter to send echo request to "+
+        destination_hexhash+
+        " (Ctrl-C to quit)"
+    )
+
+    # We enter a loop that runs until the user exits.
+    # If the user hits enter, we will try to send an
+    # echo request to the destination specified on the
+    # command line.
+    while True:
+        input()
+        
+        # Let's first check if RNS knows a path to the destination.
+        # If it does, we'll load the server identity and create a packet
+        if RNS.Transport.has_path(destination_hash):
+
+            # To address the server, we need to know it's public
+            # key, so we check if Reticulum knows this destination.
+            # This is done by calling the "recall" method of the
+            # Identity module. If the destination is known, it will
+            # return an Identity instance that can be used in
+            # outgoing destinations.
+            server_identity = RNS.Identity.recall(destination_hash)
+
+            # We got the correct identity instance from the
+            # recall method, so let's create an outgoing
+            # destination. We use the naming convention:
+            # example_utilities.ratchet.echo.request
+            # This matches the naming we specified in the
+            # server part of the code.
+            request_destination = RNS.Destination(
+                server_identity,
+                RNS.Destination.OUT,
+                RNS.Destination.SINGLE,
+                APP_NAME,
+                "ratchet",
+                "echo",
+                "request"
+            )
+
+            # The destination is ready, so let's create a packet.
+            # We set the destination to the request_destination
+            # that was just created, and the only data we add
+            # is a random hash.
+            echo_request = RNS.Packet(request_destination, RNS.Identity.get_random_hash())
+
+            # Send the packet! If the packet is successfully
+            # sent, it will return a PacketReceipt instance.
+            packet_receipt = echo_request.send()
+
+            # If the user specified a timeout, we set this
+            # timeout on the packet receipt, and configure
+            # a callback function, that will get called if
+            # the packet times out.
+            if timeout != None:
+                packet_receipt.set_timeout(timeout)
+                packet_receipt.set_timeout_callback(packet_timed_out)
+
+            # We can then set a delivery callback on the receipt.
+            # This will get automatically called when a proof for
+            # this specific packet is received from the destination.
+            packet_receipt.set_delivery_callback(packet_delivered)
+
+            # Tell the user that the echo request was sent
+            RNS.log("Sent echo request to "+RNS.prettyhexrep(request_destination.hash))
+        else:
+            # If we do not know this destination, tell the
+            # user to wait for an announce to arrive.
+            RNS.log("Destination is not yet known. Requesting path...")
+            RNS.log("Hit enter to manually retry once an announce is received.")
+            RNS.Transport.request_path(destination_hash)
+
+# This function is called when our reply destination
+# receives a proof packet.
+def packet_delivered(receipt):
+    global reticulum
+
+    if receipt.status == RNS.PacketReceipt.DELIVERED:
+        rtt = receipt.get_rtt()
+        if (rtt >= 1):
+            rtt = round(rtt, 3)
+            rttstring = str(rtt)+" seconds"
+        else:
+            rtt = round(rtt*1000, 3)
+            rttstring = str(rtt)+" milliseconds"
+
+        reception_stats = ""
+        if reticulum.is_connected_to_shared_instance:
+            reception_rssi = reticulum.get_packet_rssi(receipt.proof_packet.packet_hash)
+            reception_snr  = reticulum.get_packet_snr(receipt.proof_packet.packet_hash)
+
+            if reception_rssi != None:
+                reception_stats += " [RSSI "+str(reception_rssi)+" dBm]"
+            
+            if reception_snr != None:
+                reception_stats += " [SNR "+str(reception_snr)+" dB]"
+
+        else:
+            if receipt.proof_packet != None:
+                if receipt.proof_packet.rssi != None:
+                    reception_stats += " [RSSI "+str(receipt.proof_packet.rssi)+" dBm]"
+                
+                if receipt.proof_packet.snr != None:
+                    reception_stats += " [SNR "+str(receipt.proof_packet.snr)+" dB]"
+
+        RNS.log(
+            "Valid reply received from "+
+            RNS.prettyhexrep(receipt.destination.hash)+
+            ", round-trip time is "+rttstring+
+            reception_stats
+        )
+
+# This function is called if a packet times out.
+def packet_timed_out(receipt):
+    if receipt.status == RNS.PacketReceipt.FAILED:
+        RNS.log("Packet "+RNS.prettyhexrep(receipt.hash)+" timed out")
+
+
+##########################################################
+#### Program Startup #####################################
+##########################################################
+
+# This part of the program gets run at startup,
+# and parses input from the user, and then starts
+# the desired program mode.
+if __name__ == "__main__":
+    try:
+        parser = argparse.ArgumentParser(description="Simple ratcheted echo server and client utility")
+
+        parser.add_argument(
+            "-s",
+            "--server",
+            action="store_true",
+            help="wait for incoming packets from clients"
+        )
+
+        parser.add_argument(
+            "-t",
+            "--timeout",
+            action="store",
+            metavar="s",
+            default=None,
+            help="set a reply timeout in seconds",
+            type=float
+        )
+
+        parser.add_argument("--config",
+            action="store",
+            default=None,
+            help="path to alternative Reticulum config directory",
+            type=str
+        )
+
+        parser.add_argument(
+            "destination",
+            nargs="?",
+            default=None,
+            help="hexadecimal hash of the server destination",
+            type=str
+        )
+
+        args = parser.parse_args()
+
+        if args.server:
+            configarg=None
+            if args.config:
+                configarg = args.config
+            server(configarg)
+        else:
+            if args.config:
+                configarg = args.config
+            else:
+                configarg = None
+
+            if args.timeout:
+                timeoutarg = float(args.timeout)
+            else:
+                timeoutarg = None
+
+            if (args.destination == None):
+                print("")
+                parser.print_help()
+                print("")
+            else:
+                client(args.destination, configarg, timeout=timeoutarg)
+    except KeyboardInterrupt:
+        print("")
+        exit()

README.md

@@ -306,9 +306,11 @@ general-purpose CPUs and on microcontrollers. The necessary primitives are:
 - X22519 for ECDH key exchanges
 - HKDF for key derivation
 - Modified Fernet for encrypted tokens
-  - AES-128 in CBC mode
-  - HMAC for message authentication
-  - No Fernet version and timestamp fields
+  - Ephemeral keys derived from an ECDH key exchange on Curve25519
+  - AES-128 in CBC mode with PKCS7 padding
+  - HMAC using SHA256 for message authentication
+  - IVs are generated through os.urandom()
+  - No Fernet version and timestamp metadata fields
 - SHA-256
 - SHA-512
 

RNS/Destination.py

@@ -1,6 +1,6 @@
 # MIT License
 #
-# Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors
+# Copyright (c) 2016-2024 Mark Qvist / unsigned.io and contributors
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -20,11 +20,13 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
+import os
 import math
 import time
 import RNS
 
 from RNS.Cryptography import Fernet
+from .vendor import umsgpack as umsgpack
 
 class Callbacks:
     def __init__(self):
@@ -38,14 +40,14 @@ class Destination:
     instances are used both to create outgoing and incoming endpoints. The
     destination type will decide if encryption, and what type, is used in
     communication with the endpoint. A destination can also announce its
-    presence on the network, which will also distribute necessary keys for
+    presence on the network, which will distribute necessary keys for
     encrypted communication with it.
 
     :param identity: An instance of :ref:`RNS.Identity<api-identity>`. Can hold only public keys for an outgoing destination, or holding private keys for an ingoing.
     :param direction: ``RNS.Destination.IN`` or ``RNS.Destination.OUT``.
     :param type: ``RNS.Destination.SINGLE``, ``RNS.Destination.GROUP`` or ``RNS.Destination.PLAIN``.
     :param app_name: A string specifying the app name.
-    :param \*aspects: Any non-zero number of string arguments.
+    :param \\*aspects: Any non-zero number of string arguments.
     """
 
     # Constants
@@ -71,6 +73,16 @@ class Destination:
 
     PR_TAG_WINDOW = 30
 
+    RATCHET_COUNT    = 512
+    """
+    The default number of generated ratchet keys a destination will retain, if it has ratchets enabled.
+    """
+
+    RATCHET_INTERVAL = 30*60
+    """
+    The minimum interval between rotating ratchet keys, in seconds.
+    """
+
     @staticmethod
     def expand_name(identity, app_name, *aspects):
         """
@@ -137,6 +149,12 @@ class Destination:
         self.type = type
         self.direction = direction
         self.proof_strategy = Destination.PROVE_NONE
+        self.ratchets = None
+        self.ratchets_path = None
+        self.ratchet_interval = Destination.RATCHET_INTERVAL
+        self.retained_ratchets = Destination.RATCHET_COUNT
+        self.latest_ratchet_time = None
+        self.__enforce_ratchets = False
         self.mtu = 0
 
         self.path_responses = {}
@@ -170,6 +188,38 @@ class Destination:
         """
         return "<"+self.name+"/"+self.hexhash+">"
 
+    def _clean_ratchets(self):
+        if self.ratchets != None:
+            if len (self.ratchets) > self.retained_ratchets:
+                self.ratchets = self.ratchets[:Destination.RATCHET_COUNT]
+
+    def _persist_ratchets(self):
+        try:
+            packed_ratchets = umsgpack.packb(self.ratchets)
+            persisted_data = {"signature": self.sign(packed_ratchets), "ratchets": packed_ratchets}
+            ratchets_file = open(self.ratchets_path, "wb")
+            ratchets_file.write(umsgpack.packb(persisted_data))
+            ratchets_file.close()
+        except Exception as e:
+            self.ratchets = None
+            self.ratchets_path = None
+            raise OSError("Could not write ratchet file contents for "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR)
+
+    def rotate_ratchets(self):
+        if self.ratchets != None:
+            now = time.time()
+            if now > self.latest_ratchet_time+self.ratchet_interval:
+                RNS.log("Rotating ratchets for "+str(self), RNS.LOG_DEBUG)
+                new_ratchet = RNS.Identity._generate_ratchet()
+                self.ratchets.insert(0, new_ratchet)
+                self.latest_ratchet_time = now
+                self._clean_ratchets()
+                self._persist_ratchets()
+            return True
+        else:
+            raise SystemError("Cannot rotate ratchet on "+str(self)+", ratchets are not enabled")
+
+        return False
 
     def announce(self, app_data=None, path_response=False, attached_interface=None, tag=None, send=True):
         """
@@ -185,6 +235,7 @@ class Destination:
         if self.direction != Destination.IN:
             raise TypeError("Only IN destination types can be announced")
         
+        ratchet = b""
         now = time.time()
         stale_responses = []
         for entry_tag in self.path_responses:
@@ -211,6 +262,13 @@ class Destination:
             destination_hash = self.hash
             random_hash = RNS.Identity.get_random_hash()[0:5]+int(time.time()).to_bytes(5, "big")
 
+            if self.ratchets != None:
+                self.rotate_ratchets()
+                ratchet = RNS.Identity._ratchet_public_bytes(self.ratchets[0])
+
+                # TODO: Remove at some point
+                RNS.log(f"Including ratchet {RNS.prettyhexrep(RNS.Identity.truncated_hash(ratchet))} in announce", RNS.LOG_EXTREME)
+
             if app_data == None and self.default_app_data != None:
                 if isinstance(self.default_app_data, bytes):
                     app_data = self.default_app_data
@@ -219,13 +277,12 @@ class Destination:
                     if isinstance(returned_app_data, bytes):
                         app_data = returned_app_data
             
-            signed_data = self.hash+self.identity.get_public_key()+self.name_hash+random_hash
+            signed_data = self.hash+self.identity.get_public_key()+self.name_hash+random_hash+ratchet
             if app_data != None:
                 signed_data += app_data
 
             signature = self.identity.sign(signed_data)
-
-            announce_data = self.identity.get_public_key()+self.name_hash+random_hash+signature
+            announce_data = self.identity.get_public_key()+self.name_hash+random_hash+ratchet+signature
 
             if app_data != None:
                 announce_data += app_data
@@ -237,8 +294,13 @@ class Destination:
         else:
             announce_context = RNS.Packet.NONE
 
-        announce_packet = RNS.Packet(self, announce_data, RNS.Packet.ANNOUNCE, context = announce_context, attached_interface = attached_interface)
+        if ratchet:
+            context_flag = RNS.Packet.FLAG_SET
+        else:
+            context_flag = RNS.Packet.FLAG_UNSET
 
+        announce_packet = RNS.Packet(self, announce_data, RNS.Packet.ANNOUNCE, context = announce_context,
+                                     attached_interface = attached_interface, context_flag=context_flag)
         if send:
             announce_packet.send()
         else:
@@ -298,7 +360,6 @@ class Destination:
         else:
             self.proof_strategy = proof_strategy
 
-
     def register_request_handler(self, path, response_generator = None, allow = ALLOW_NONE, allowed_list = None):
         """
         Registers a request handler.
@@ -320,7 +381,6 @@ class Destination:
             request_handler = [path, response_generator, allow, allowed_list]
             self.request_handlers[path_hash] = request_handler
 
-
     def deregister_request_handler(self, path):
         """
         Deregisters a request handler.
@@ -335,8 +395,6 @@ class Destination:
         else:
             return False
 
-        
-
     def receive(self, packet):
         if packet.packet_type == RNS.Packet.LINKREQUEST:
             plaintext = packet.data
@@ -351,13 +409,99 @@ class Destination:
                         except Exception as e:
                             RNS.log("Error while executing receive callback from "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR)
 
-
     def incoming_link_request(self, data, packet):
         if self.accept_link_requests:
             link = RNS.Link.validate_request(self, data, packet)
             if link != None:
                 self.links.append(link)
 
+    def enable_ratchets(self, ratchets_path):
+        """
+        Enables ratchets on the destination. When ratchets are enabled, Reticulum will automatically rotate
+        the keys used to encrypt packets to this destination, and include the latest ratchet key in announces.
+
+        Enabling ratchets on a destination will provide forward secrecy for packets sent to that destination,
+        even when sent outside a ``Link``. The normal Reticulum ``Link`` establishment procedure already performs
+        its own ephemeral key exchange for each link establishment, which means that ratchets are not necessary
+        to provide forward secrecy for links.
+
+        Enabling ratchets will have a small impact on announce size, adding 32 bytes to every sent announce.
+
+        :param ratchets_path: The path to a file to store ratchet data in.
+        :returns: True if the operation succeeded, otherwise False.
+        """
+        if ratchets_path != None:
+            self.latest_ratchet_time = 0
+            if os.path.isfile(ratchets_path):
+                try:
+                    ratchets_file = open(ratchets_path, "rb")
+                    persisted_data = umsgpack.unpackb(ratchets_file.read())
+                    if "signature" in persisted_data and "ratchets" in persisted_data:
+                        if self.identity.validate(persisted_data["signature"], persisted_data["ratchets"]):
+                            self.ratchets = umsgpack.unpackb(persisted_data["ratchets"])
+                            self.ratchets_path = ratchets_path
+                        else:
+                            raise KeyError("Invalid ratchet file signature")
+
+                except Exception as e:
+                    self.ratchets = None
+                    self.ratchets_path = None
+                    raise OSError("Could not read ratchet file contents for "+str(self)+". The contained exception was: "+str(e), RNS.LOG_ERROR)
+            else:
+                RNS.log("No existing ratchet data found, initialising new ratchet file for "+str(self), RNS.LOG_DEBUG)
+                self.ratchets = []
+                self.ratchets_path = ratchets_path
+                self._persist_ratchets()
+
+            # TODO: Remove at some point
+            RNS.log("Ratchets enabled on "+str(self), RNS.LOG_DEBUG)
+            return True
+
+        else:
+            raise ValueError("No ratchet file path specified for "+str(self))
+
+    def enforce_ratchets(self):
+        """
+        When ratchet enforcement is enabled, this destination will never accept packets that use its
+        base Identity key for encryption, but only accept packets encrypted with one of the retained
+        ratchet keys.
+        """
+        if self.ratchets != None:
+            self.__enforce_ratchets = True
+            RNS.log("Ratchets enforced on "+str(self), RNS.LOG_DEBUG)
+            return True
+        else:
+            return False
+
+    def set_retained_ratchets(self, retained_ratchets):
+        """
+        Sets the number of previously generated ratchet keys this destination will retain,
+        and try to use when decrypting incoming packets. Defaults to ``Destination.RATCHET_COUNT``.
+
+        :param retained_ratchets: The number of generated ratchets to retain.
+        :returns: True if the operation succeeded, False if not.
+        """
+        if isinstance(retained_ratchets, int) and retained_ratchets > 0:
+            self.retained_ratchets = retained_ratchets
+            self._clean_ratchets()
+            return True
+        else:
+            return False
+
+    def set_ratchet_interval(self, interval):
+        """
+        Sets the minimum interval in seconds between ratchet key rotation.
+        Defaults to ``Destination.RATCHET_INTERVAL``.
+
+        :param interval: The minimum interval in seconds.
+        :returns: True if the operation succeeded, False if not.
+        """
+        if isinstance(interval, int) and interval > 0:
+            self.ratchet_interval = interval
+            return True
+        else:
+            return False
+
     def create_keys(self):
         """
         For a ``RNS.Destination.GROUP`` type destination, creates a new symmetric key.
@@ -374,7 +518,6 @@ class Destination:
             self.prv_bytes = Fernet.generate_key()
             self.prv = Fernet(self.prv_bytes)
 
-
     def get_private_key(self):
         """
         For a ``RNS.Destination.GROUP`` type destination, returns the symmetric private key.
@@ -388,7 +531,6 @@ class Destination:
         else:
             return self.prv_bytes
 
-
     def load_private_key(self, key):
         """
         For a ``RNS.Destination.GROUP`` type destination, loads a symmetric private key.
@@ -412,7 +554,6 @@ class Destination:
         else:
             raise TypeError("A single destination holds keys through an Identity instance")
 
-
     def encrypt(self, plaintext):
         """
         Encrypts information for ``RNS.Destination.SINGLE`` or ``RNS.Destination.GROUP`` type destination.
@@ -424,7 +565,7 @@ class Destination:
             return plaintext
 
         if self.type == Destination.SINGLE and self.identity != None:
-            return self.identity.encrypt(plaintext)
+            return self.identity.encrypt(plaintext, ratchet=RNS.Identity.get_ratchet(self.hash))
 
         if self.type == Destination.GROUP:
             if hasattr(self, "prv") and self.prv != None:
@@ -436,8 +577,6 @@ class Destination:
             else:
                 raise ValueError("No private key held by GROUP destination. Did you create or load one?")
 
-
-
     def decrypt(self, ciphertext):
         """
         Decrypts information for ``RNS.Destination.SINGLE`` or ``RNS.Destination.GROUP`` type destination.
@@ -449,7 +588,7 @@ class Destination:
             return ciphertext
 
         if self.type == Destination.SINGLE and self.identity != None:
-            return self.identity.decrypt(ciphertext)
+            return self.identity.decrypt(ciphertext, ratchets=self.ratchets, enforce_ratchets=self.__enforce_ratchets)
 
         if self.type == Destination.GROUP:
             if hasattr(self, "prv") and self.prv != None:
@@ -461,7 +600,6 @@ class Destination:
             else:
                 raise ValueError("No private key held by GROUP destination. Did you create or load one?")
 
-
     def sign(self, message):
         """
         Signs information for ``RNS.Destination.SINGLE`` type destination.

RNS/Identity.py

@@ -1,6 +1,6 @@
 # MIT License
 #
-# Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors.
+# Copyright (c) 2016-2024 Mark Qvist / unsigned.io and contributors.
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -26,6 +26,7 @@ import RNS
 import time
 import atexit
 import hashlib
+import threading
 
 from .vendor import umsgpack as umsgpack
 
@@ -49,7 +50,19 @@ class Identity:
 
     KEYSIZE     = 256*2
     """
-    X25519 key size in bits. A complete key is the concatenation of a 256 bit encryption key, and a 256 bit signing key.
+    X.25519 key size in bits. A complete key is the concatenation of a 256 bit encryption key, and a 256 bit signing key.
+    """
+
+    RATCHETSIZE = 256
+    """
+    X.25519 ratchet key size in bits.
+    """
+
+    RATCHET_EXPIRY = 60*60*24*30
+    """
+    The expiry time for received ratchets in seconds, defaults to 30 days. Reticulum will always use the most recently
+    announced ratchet, and remember it for up to ``RATCHET_EXPIRY`` since receiving it, after which it will be discarded.
+    If a newer ratchet is announced in the meantime, it will be replace the already known ratchet.
     """
 
     # Non-configurable constants
@@ -67,6 +80,9 @@ class Identity:
 
     # Storage
     known_destinations = {}
+    known_ratchets = {}
+
+    ratchet_persist_lock = threading.Lock()
 
     @staticmethod
     def remember(packet_hash, destination_hash, public_key, app_data = None):
@@ -221,20 +237,135 @@ class Identity:
         """
         return Identity.truncated_hash(os.urandom(Identity.TRUNCATED_HASHLENGTH//8))
 
+    @staticmethod
+    def _ratchet_public_bytes(ratchet):
+        return X25519PrivateKey.from_private_bytes(ratchet).public_key().public_bytes()
+
+    @staticmethod
+    def _generate_ratchet():
+        ratchet_prv = X25519PrivateKey.generate()
+        ratchet_pub = ratchet_prv.public_key()
+        return ratchet_prv.private_bytes()
+
+    @staticmethod
+    def _remember_ratchet(destination_hash, ratchet):
+        # TODO: Remove at some point
+        RNS.log(f"Remembering ratchet {RNS.prettyhexrep(Identity.truncated_hash(ratchet))} for {RNS.prettyhexrep(destination_hash)}", RNS.LOG_EXTREME)
+        try:
+            Identity.known_ratchets[destination_hash] = ratchet
+
+            if not RNS.Transport.owner.is_connected_to_shared_instance:
+                def persist_job():
+                    with Identity.ratchet_persist_lock:
+                        hexhash = RNS.hexrep(destination_hash, delimit=False)
+                        ratchet_data = {"ratchet": ratchet, "received": time.time()}
+
+                        ratchetdir = RNS.Reticulum.storagepath+"/ratchets"
+                        
+                        if not os.path.isdir(ratchetdir):
+                            os.makedirs(ratchetdir)
+
+                        outpath   = f"{ratchetdir}/{hexhash}.out"
+                        finalpath = f"{ratchetdir}/{hexhash}"
+                        ratchet_file = open(outpath, "wb")
+                        ratchet_file.write(umsgpack.packb(ratchet_data))
+                        ratchet_file.close()
+                        os.rename(outpath, finalpath)
+
+                
+                threading.Thread(target=persist_job, daemon=True).start()
+
+        except Exception as e:
+            RNS.log(f"Could not persist ratchet for {RNS.prettyhexrep(destination_hash)} to storage.", RNS.LOG_ERROR)
+            RNS.log(f"The contained exception was: {e}")
+            RNS.trace_exception(e)
+
+    @staticmethod
+    def _clean_ratchets():
+        RNS.log("Cleaning ratchets...", RNS.LOG_DEBUG)
+        try:
+            now = time.time()
+            ratchetdir = RNS.Reticulum.storagepath+"/ratchets"
+            for filename in os.listdir(ratchetdir):
+                try:
+                    expired = False
+                    with open(f"{ratchetdir}/{filename}", "rb") as rf:
+                        ratchet_data = umsgpack.unpackb(rf.read())
+                        if now > ratchet_data["received"]+Identity.RATCHET_EXPIRY:
+                            expired = True
+
+                    if expired:
+                        os.unlink(f"{ratchetdir}/{filename}")
+
+                except Exception as e:
+                    RNS.log(f"An error occurred while cleaning ratchets, in the processing of {ratchetdir}/{filename}.", RNS.LOG_ERROR)
+                    RNS.log(f"The contained exception was: {e}", RNS.LOG_ERROR)
+
+        except Exception as e:
+            RNS.log(f"An error occurred while cleaning ratchets. The contained exception was: {e}", RNS.LOG_ERROR)
+
+    @staticmethod
+    def get_ratchet(destination_hash):
+        if not destination_hash in Identity.known_ratchets:
+            ratchetdir = RNS.Reticulum.storagepath+"/ratchets"
+            hexhash = RNS.hexrep(destination_hash, delimit=False)
+            ratchet_path = f"{ratchetdir}/hexhash"
+            if os.path.isfile(ratchet_path):
+                try:
+                    ratchet_file = open(ratchet_path, "rb")
+                    ratchet_data = umsgpack.unpackb(ratchets_file.read())
+                    if time.time() < ratchet_data["received"]+Identity.RATCHET_EXPIRY and len(ratchet_data["ratchet"]) == Identity.RATCHETSIZE//8:
+                        Identity.known_ratchets[destination_hash] = ratchet_data["ratchet"]
+                    else:
+                        return None
+                
+                except Exception as e:
+                    RNS.log(f"An error occurred while loading ratchet data for {RNS.prettyhexrep(destination_hash)} from storage.", RNS.LOG_ERROR)
+                    RNS.log(f"The contained exception was: {e}", RNS.LOG_ERROR)
+                    return None
+
+        if destination_hash in Identity.known_ratchets:
+            return Identity.known_ratchets[destination_hash]
+        else:
+            RNS.log(f"Could not load ratchet for {RNS.prettyhexrep(destination_hash)}", RNS.LOG_DEBUG)
+            return None
+
     @staticmethod
     def validate_announce(packet, only_validate_signature=False):
         try:
             if packet.packet_type == RNS.Packet.ANNOUNCE:
+                keysize       = Identity.KEYSIZE//8
+                ratchetsize   = Identity.RATCHETSIZE//8
+                name_hash_len = Identity.NAME_HASH_LENGTH//8
+                sig_len       = Identity.SIGLENGTH//8
                 destination_hash = packet.destination_hash
-                public_key = packet.data[:Identity.KEYSIZE//8]
-                name_hash = packet.data[Identity.KEYSIZE//8:Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8]
-                random_hash = packet.data[Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8:Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8+10]
-                signature = packet.data[Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8+10:Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8+10+Identity.SIGLENGTH//8]
-                app_data = b""
-                if len(packet.data) > Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8+10+Identity.SIGLENGTH//8:
-                    app_data = packet.data[Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8+10+Identity.SIGLENGTH//8:]
 
-                signed_data = destination_hash+public_key+name_hash+random_hash+app_data
+                # Get public key bytes from announce
+                public_key = packet.data[:keysize]
+
+                # If the packet context flag is set,
+                # this announce contains a new ratchet
+                if packet.context_flag == RNS.Packet.FLAG_SET:
+                    name_hash   = packet.data[keysize:keysize+name_hash_len ]
+                    random_hash = packet.data[keysize+name_hash_len:keysize+name_hash_len+10]
+                    ratchet     = packet.data[keysize+name_hash_len+10:keysize+name_hash_len+10+ratchetsize]
+                    signature   = packet.data[keysize+name_hash_len+10+ratchetsize:keysize+name_hash_len+10+ratchetsize+sig_len]
+                    app_data    = b""
+                    if len(packet.data) > keysize+name_hash_len+10+sig_len+ratchetsize:
+                        app_data = packet.data[keysize+name_hash_len+10+sig_len+ratchetsize:]
+
+                # If the packet context flag is not set,
+                # this announce does not contain a ratchet
+                else:
+                    ratchet     = b""
+                    name_hash   = packet.data[keysize:keysize+name_hash_len]
+                    random_hash = packet.data[keysize+name_hash_len:keysize+name_hash_len+10]
+                    signature   = packet.data[keysize+name_hash_len+10:keysize+name_hash_len+10+sig_len]
+                    app_data    = b""
+                    if len(packet.data) > keysize+name_hash_len+10+sig_len:
+                        app_data = packet.data[keysize+name_hash_len+10+sig_len:]
+
+                signed_data = destination_hash+public_key+name_hash+random_hash+ratchet+app_data
 
                 if not len(packet.data) > Identity.KEYSIZE//8+Identity.NAME_HASH_LENGTH//8+10+Identity.SIGLENGTH//8:
                     app_data = None
@@ -281,6 +412,9 @@ class Identity:
                         else:
                             RNS.log("Valid announce for "+RNS.prettyhexrep(destination_hash)+" "+str(packet.hops)+" hops away, received on "+str(packet.receiving_interface)+signal_str, RNS.LOG_EXTREME)
 
+                        if ratchet:
+                            Identity._remember_ratchet(destination_hash, ratchet)
+
                         return True
 
                     else:
@@ -469,7 +603,7 @@ class Identity:
     def get_context(self):
         return None
 
-    def encrypt(self, plaintext):
+    def encrypt(self, plaintext, ratchet=None):
         """
         Encrypts information for the identity.
 
@@ -481,7 +615,14 @@ class Identity:
             ephemeral_key = X25519PrivateKey.generate()
             ephemeral_pub_bytes = ephemeral_key.public_key().public_bytes()
 
-            shared_key = ephemeral_key.exchange(self.pub)
+            if ratchet != None:
+                # TODO: Remove at some point
+                RNS.log(f"Encrypting with ratchet {RNS.prettyhexrep(RNS.Identity.truncated_hash(ratchet))}", RNS.LOG_EXTREME)
+                target_public_key = X25519PublicKey.from_public_bytes(ratchet)
+            else:
+                target_public_key = self.pub
+
+            shared_key = ephemeral_key.exchange(target_public_key)
             
             derived_key = RNS.Cryptography.hkdf(
                 length=32,
@@ -499,7 +640,7 @@ class Identity:
             raise KeyError("Encryption failed because identity does not hold a public key")
 
 
-    def decrypt(self, ciphertext_token):
+    def decrypt(self, ciphertext_token, ratchets=None, enforce_ratchets=False):
         """
         Decrypts information for the identity.
 
@@ -513,19 +654,46 @@ class Identity:
                 try:
                     peer_pub_bytes = ciphertext_token[:Identity.KEYSIZE//8//2]
                     peer_pub = X25519PublicKey.from_public_bytes(peer_pub_bytes)
-
-                    shared_key = self.prv.exchange(peer_pub)
-
-                    derived_key = RNS.Cryptography.hkdf(
-                        length=32,
-                        derive_from=shared_key,
-                        salt=self.get_salt(),
-                        context=self.get_context(),
-                    )
-
-                    fernet = Fernet(derived_key)
                     ciphertext = ciphertext_token[Identity.KEYSIZE//8//2:]
-                    plaintext = fernet.decrypt(ciphertext)
+
+                    if ratchets:
+                        for ratchet in ratchets:
+                            try:
+                                ratchet_prv = X25519PrivateKey.from_private_bytes(ratchet)
+                                shared_key = ratchet_prv.exchange(peer_pub)
+                                derived_key = RNS.Cryptography.hkdf(
+                                    length=32,
+                                    derive_from=shared_key,
+                                    salt=self.get_salt(),
+                                    context=self.get_context(),
+                                )
+
+                                fernet = Fernet(derived_key)
+                                plaintext = fernet.decrypt(ciphertext)
+                                
+                                # TODO: Remove at some point
+                                RNS.log(f"Decrypted with ratchet {RNS.prettyhexrep(RNS.Identity.truncated_hash(ratchet_prv.public_key().public_bytes()))}", RNS.LOG_EXTREME)
+                                
+                                break
+                            
+                            except Exception as e:
+                                pass
+
+                    if enforce_ratchets and plaintext == None:
+                        RNS.log("Decryption with ratchet enforcement by "+RNS.prettyhexrep(self.hash)+" failed. Dropping packet.", RNS.LOG_DEBUG)
+                        return None
+
+                    if plaintext == None:
+                        shared_key = self.prv.exchange(peer_pub)
+                        derived_key = RNS.Cryptography.hkdf(
+                            length=32,
+                            derive_from=shared_key,
+                            salt=self.get_salt(),
+                            context=self.get_context(),
+                        )
+
+                        fernet = Fernet(derived_key)
+                        plaintext = fernet.decrypt(ciphertext)
 
                 except Exception as e:
                     RNS.log("Decryption by "+RNS.prettyhexrep(self.hash)+" failed: "+str(e), RNS.LOG_DEBUG)

RNS/Interfaces/RNodeMultiInterface.py

@@ -116,40 +116,42 @@ class KISS():
     SX1280    = 0x21
 
     def int_data_cmd_to_index(int_data_cmd):
-        match int_data_cmd:
-            case KISS.CMD_INT0_DATA:
-                return 0
-            case KISS.CMD_INT1_DATA:
-                return 1
-            case KISS.CMD_INT2_DATA:
-                return 2
-            case KISS.CMD_INT3_DATA:
-                return 3
-            case KISS.CMD_INT4_DATA:
-                return 4
-            case KISS.CMD_INT5_DATA:
-                return 5
-            case KISS.CMD_INT6_DATA:
-                return 6
-            case KISS.CMD_INT7_DATA:
-                return 7
-            case KISS.CMD_INT8_DATA:
-                return 8
-            case KISS.CMD_INT9_DATA:
-                return 9
-            case KISS.CMD_INT10_DATA:
-                return 10
-            case KISS.CMD_INT11_DATA:
-                return 11
+        if int_data_cmd == KISS.CMD_INT0_DATA:
+            return 0
+        elif int_data_cmd == KISS.CMD_INT1_DATA:
+            return 1
+        elif int_data_cmd == KISS.CMD_INT2_DATA:
+            return 2
+        elif int_data_cmd == KISS.CMD_INT3_DATA:
+            return 3
+        elif int_data_cmd == KISS.CMD_INT4_DATA:
+            return 4
+        elif int_data_cmd == KISS.CMD_INT5_DATA:
+            return 5
+        elif int_data_cmd == KISS.CMD_INT6_DATA:
+            return 6
+        elif int_data_cmd == KISS.CMD_INT7_DATA:
+            return 7
+        elif int_data_cmd == KISS.CMD_INT8_DATA:
+            return 8
+        elif int_data_cmd == KISS.CMD_INT9_DATA:
+            return 9
+        elif int_data_cmd == KISS.CMD_INT10_DATA:
+            return 10
+        elif int_data_cmd == KISS.CMD_INT11_DATA:
+            return 11
+        else:
+            return 0
 
     def interface_type_to_str(interface_type):
-        match interface_type:
-            case KISS.SX126X | KISS.SX1262:
+        if interface_type == KISS.SX126X or interface_type == KISS.SX1262:
                 return "SX126X"
-            case KISS.SX127X | KISS.SX1276 | KISS.SX1278:
-                return "SX127X"
-            case KISS.SX128X | KISS.SX1280:
-                return "SX128X"
+        elif interface_type == KISS.SX127X or interface_type == KISS.SX1276 or interface_type == KISS.SX1278:
+            return "SX127X"
+        elif interface_type == KISS.SX128X or interface_type == KISS.SX1280:
+            return "SX128X"
+        else:
+            return "SX127X"
 
     @staticmethod
     def escape(data):
@@ -915,46 +917,45 @@ class RNodeSubInterface(Interface):
 
         super().__init__()
         
-        match index:
-            case 0:
-                sel_cmd = KISS.CMD_SEL_INT0
-                data_cmd= KISS.CMD_INT0_DATA
-            case 1:
-                sel_cmd = KISS.CMD_SEL_INT1
-                data_cmd= KISS.CMD_INT1_DATA
-            case 2:
-                sel_cmd = KISS.CMD_SEL_INT2
-                data_cmd= KISS.CMD_INT2_DATA
-            case 3:
-                sel_cmd = KISS.CMD_SEL_INT3
-                data_cmd= KISS.CMD_INT3_DATA
-            case 4:
-                sel_cmd = KISS.CMD_SEL_INT4
-                data_cmd= KISS.CMD_INT4_DATA
-            case 5:
-                sel_cmd = KISS.CMD_SEL_INT5
-                data_cmd= KISS.CMD_INT5_DATA
-            case 6:
-                sel_cmd = KISS.CMD_SEL_INT6
-                data_cmd= KISS.CMD_INT6_DATA
-            case 7:
-                sel_cmd = KISS.CMD_SEL_INT7
-                data_cmd= KISS.CMD_INT7_DATA
-            case 8:
-                sel_cmd = KISS.CMD_SEL_INT8
-                data_cmd= KISS.CMD_INT8_DATA
-            case 9:
-                sel_cmd = KISS.CMD_SEL_INT9
-                data_cmd= KISS.CMD_INT9_DATA
-            case 10:
-                sel_cmd = KISS.CMD_SEL_INT10
-                data_cmd= KISS.CMD_INT10_DATA
-            case 11:
-                sel_cmd = KISS.CMD_SEL_INT11
-                data_cmd= KISS.CMD_INT11_DATA
-            case _:
-                sel_cmd = KISS.CMD_SEL_INT0
-                data_cmd= KISS.CMD_INT0_DATA
+        if index == 0:
+            sel_cmd = KISS.CMD_SEL_INT0
+            data_cmd= KISS.CMD_INT0_DATA
+        elif index == 1:
+            sel_cmd = KISS.CMD_SEL_INT1
+            data_cmd= KISS.CMD_INT1_DATA
+        elif index == 2:
+            sel_cmd = KISS.CMD_SEL_INT2
+            data_cmd= KISS.CMD_INT2_DATA
+        elif index == 3:
+            sel_cmd = KISS.CMD_SEL_INT3
+            data_cmd= KISS.CMD_INT3_DATA
+        elif index == 4:
+            sel_cmd = KISS.CMD_SEL_INT4
+            data_cmd= KISS.CMD_INT4_DATA
+        elif index == 5:
+            sel_cmd = KISS.CMD_SEL_INT5
+            data_cmd= KISS.CMD_INT5_DATA
+        elif index == 6:
+            sel_cmd = KISS.CMD_SEL_INT6
+            data_cmd= KISS.CMD_INT6_DATA
+        elif index == 7:
+            sel_cmd = KISS.CMD_SEL_INT7
+            data_cmd= KISS.CMD_INT7_DATA
+        elif index == 8:
+            sel_cmd = KISS.CMD_SEL_INT8
+            data_cmd= KISS.CMD_INT8_DATA
+        elif index == 9:
+            sel_cmd = KISS.CMD_SEL_INT9
+            data_cmd= KISS.CMD_INT9_DATA
+        elif index == 10:
+            sel_cmd = KISS.CMD_SEL_INT10
+            data_cmd= KISS.CMD_INT10_DATA
+        elif index == 11:
+            sel_cmd = KISS.CMD_SEL_INT11
+            data_cmd= KISS.CMD_INT11_DATA
+        else:
+            sel_cmd = KISS.CMD_SEL_INT0
+            data_cmd= KISS.CMD_INT0_DATA
 
         self.owner       = owner
         self.name        = name

RNS/Link.py

@@ -1,6 +1,6 @@
 # MIT License
 #
-# Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors.
+# Copyright (c) 2016-2024 Mark Qvist / unsigned.io and contributors.
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -142,6 +142,7 @@ class Link:
             raise TypeError("Links can only be established to the \"single\" destination type")
         self.rtt = None
         self.establishment_cost = 0
+        self.establishment_rate = None
         self.callbacks = LinkCallbacks()
         self.resource_strategy = Link.ACCEPT_NONE
         self.outgoing_resources = []

RNS/Packet.py

@@ -1,6 +1,6 @@
 # MIT License
 #
-# Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors.
+# Copyright (c) 2016-2024 Mark Qvist / unsigned.io and contributors.
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -83,6 +83,10 @@ class Packet:
     LRRTT          = 0xFE   # Packet is a link request round-trip time measurement
     LRPROOF        = 0xFF   # Packet is a link request proof
 
+    # Context flag values
+    FLAG_SET       = 0x01
+    FLAG_UNSET     = 0x00
+
     # This is used to calculate allowable
     # payload sizes
     HEADER_MAXSIZE = RNS.Reticulum.HEADER_MAXSIZE
@@ -102,7 +106,9 @@ class Packet:
 
     TIMEOUT_PER_HOP = RNS.Reticulum.DEFAULT_PER_HOP_TIMEOUT
 
-    def __init__(self, destination, data, packet_type = DATA, context = NONE, transport_type = RNS.Transport.BROADCAST, header_type = HEADER_1, transport_id = None, attached_interface = None, create_receipt = True):
+    def __init__(self, destination, data, packet_type = DATA, context = NONE, transport_type = RNS.Transport.BROADCAST,
+                 header_type = HEADER_1, transport_id = None, attached_interface = None, create_receipt = True, context_flag=FLAG_UNSET):
+
         if destination != None:
             if transport_type == None:
                 transport_type = RNS.Transport.BROADCAST
@@ -111,6 +117,7 @@ class Packet:
             self.packet_type    = packet_type
             self.transport_type = transport_type
             self.context        = context
+            self.context_flag   = context_flag
 
             self.hops           = 0;
             self.destination    = destination
@@ -142,9 +149,10 @@ class Packet:
 
     def get_packed_flags(self):
         if self.context == Packet.LRPROOF:
-            packed_flags = (self.header_type << 6) | (self.transport_type << 4) | (RNS.Destination.LINK << 2) | self.packet_type
+            packed_flags = (self.header_type << 6) | (self.context_flag << 5) | (self.transport_type << 4) | (RNS.Destination.LINK << 2) | self.packet_type
         else:
-            packed_flags = (self.header_type << 6) | (self.transport_type << 4) | (self.destination.type << 2) | self.packet_type
+            packed_flags = (self.header_type << 6) | (self.context_flag << 5) | (self.transport_type << 4) | (self.destination.type << 2) | self.packet_type
+
         return packed_flags
 
     def pack(self):
@@ -216,7 +224,8 @@ class Packet:
             self.hops  = self.raw[1]
 
             self.header_type      = (self.flags & 0b01000000) >> 6
-            self.transport_type   = (self.flags & 0b00110000) >> 4
+            self.context_flag     = (self.flags & 0b00100000) >> 5
+            self.transport_type   = (self.flags & 0b00010000) >> 4
             self.destination_type = (self.flags & 0b00001100) >> 2
             self.packet_type      = (self.flags & 0b00000011)
 

RNS/Reticulum.py

@@ -1,6 +1,6 @@
 # MIT License
 #
-# Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors.
+# Copyright (c) 2016-2024 Mark Qvist / unsigned.io and contributors.
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -295,6 +295,7 @@ class Reticulum:
 
     def __start_jobs(self):
         if self.jobs_thread == None:
+            RNS.Identity._clean_ratchets()
             self.jobs_thread = threading.Thread(target=self.__jobs)
             self.jobs_thread.daemon = True
             self.jobs_thread.start()

RNS/Transport.py

@@ -1,6 +1,6 @@
 # MIT License
 #
-# Copyright (c) 2016-2023 Mark Qvist / unsigned.io and contributors.
+# Copyright (c) 2016-2024 Mark Qvist / unsigned.io and contributors.
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal
@@ -403,7 +403,8 @@ class Transport:
                                     header_type = RNS.Packet.HEADER_2,
                                     transport_type = Transport.TRANSPORT,
                                     transport_id = Transport.identity.hash,
-                                    attached_interface = attached_interface
+                                    attached_interface = attached_interface,
+                                    context_flag = packet.context_flag,
                                 )
 
                                 new_packet.hops = announce_entry[4]
@@ -1603,7 +1604,8 @@ class Transport:
                                                 header_type = RNS.Packet.HEADER_2,
                                                 transport_type = Transport.TRANSPORT,
                                                 transport_id = Transport.identity.hash,
-                                                attached_interface = local_interface
+                                                attached_interface = local_interface,
+                                                context_flag = packet.context_flag,
                                             )
                                             
                                             new_announce.hops = packet.hops
@@ -1620,7 +1622,8 @@ class Transport:
                                                 header_type = RNS.Packet.HEADER_2,
                                                 transport_type = Transport.TRANSPORT,
                                                 transport_id = Transport.identity.hash,
-                                                attached_interface = local_interface
+                                                attached_interface = local_interface,
+                                                context_flag = packet.context_flag,
                                             )
 
                                             new_announce.hops = packet.hops
@@ -1651,7 +1654,8 @@ class Transport:
                                     header_type = RNS.Packet.HEADER_2,
                                     transport_type = Transport.TRANSPORT,
                                     transport_id = Transport.identity.hash,
-                                    attached_interface = attached_interface
+                                    attached_interface = attached_interface,
+                                    context_flag = packet.context_flag,
                                 )
 
                                 new_announce.hops = packet.hops

RNS/_version.py

@@ -1 +1 @@
-__version__ = "0.7.6"
+__version__ = "0.7.7"

docs/manual/.buildinfo

@@ -1,4 +1,4 @@
 # Sphinx build info version 1
 # This file hashes the configuration used when building these files. When it is not found, a full rebuild will be done.
-config: 4a5b669a6756de77e9b7c6b7dc5d5702
+config: 895ecce87b0f2ca7fbb104a33248dc3e
 tags: 645f666f9bcd5a90fca523b33c5a78b7

docs/manual/_sources/understanding.rst.txt

@@ -134,10 +134,11 @@ be sufficient, even far into the future.
 By default Reticulum encrypts all data using elliptic curve cryptography and AES. Any packet sent to a
 destination is encrypted with a per-packet derived key. Reticulum can also set up an encrypted
 channel to a destination, called a *Link*. Both data sent over Links and single packets offer
-*Initiator Anonymity*, and links additionally offer *Forward Secrecy* by using an Elliptic Curve
-Diffie Hellman key exchange on Curve25519 to derive per-link ephemeral keys. The multi-hop transport,
-coordination, verification and reliability layers are fully autonomous and also based on elliptic
-curve cryptography.
+*Initiator Anonymity*. Links additionally offer *Forward Secrecy* by default, employing an Elliptic Curve
+Diffie Hellman key exchange on Curve25519 to derive per-link ephemeral keys. Asymmetric, link-less
+packet communication can also provide forward secrecy, with automatic key ratcheting, by enabling
+ratchets on a per-destination basis. The multi-hop transport, coordination, verification and reliability
+layers are fully autonomous and also based on elliptic curve cryptography.
 
 Reticulum also offers symmetric key encryption for group-oriented communications, as well as
 unencrypted packets for local broadcast purposes.
@@ -431,7 +432,7 @@ For exchanges of small amounts of information, Reticulum offers the *Packet* API
 
 * | A packet is always created with an associated destination and some payload data. When the packet is sent
     to a *single* destination type, Reticulum will automatically create an ephemeral encryption key, perform
-    an ECDH key exchange with the destination's public key, and encrypt the information.
+    an ECDH key exchange with the destination's public key (or ratchet key, if available), and encrypt the information.
 
 * | It is important to note that this key exchange does not require any network traffic. The sender already
     knows the public key of the destination from an earlier received *announce*, and can thus perform the ECDH
@@ -693,7 +694,8 @@ Wire Format
     [HEADER 2 bytes] [ADDRESSES 16/32 bytes] [CONTEXT 1 byte] [DATA 0-465 bytes]
 
     * The HEADER field is 2 bytes long.
-      * Byte 1: [IFAC Flag], [Header Type], [Propagation Type], [Destination Type] and [Packet Type]
+      * Byte 1: [IFAC Flag], [Header Type], [Context Flag], [Propagation Type],
+                [Destination Type] and [Packet Type]
       * Byte 2: Number of hops
 
     * Interface Access Code field if the IFAC flag was set.
@@ -725,12 +727,16 @@ Wire Format
     type 2           1  Two byte header, two 16 byte address fields
 
 
+    Context Flag
+    -----------------
+    unset            0  The context flag is used for various types
+    set              1  of signalling, depending on packet context
+
+
     Propagation Types
     -----------------
-    broadcast       00
-    transport       01
-    reserved        10
-    reserved        11
+    broadcast        0
+    transport        1
 
 
     Destination Types
@@ -862,12 +868,14 @@ both on general-purpose CPUs and on microcontrollers. The necessary primitives a
 
 * HKDF for key derivation
 
-* Fernet for encrypted tokens
+* Modified Fernet for encrypted tokens
 
   * AES-128 in CBC mode
 
   * HMAC for message authentication
 
+  * No Version and Timestamp metadata included
+
 * SHA-256
 
 * SHA-512

docs/manual/_sources/whatis.rst.txt

@@ -53,9 +53,9 @@ What does Reticulum Offer?
 
 * Forward Secrecy by using ephemeral Elliptic Curve Diffie-Hellman keys on Curve25519
 
-* Reticulum uses the `Fernet <https://github.com/fernet/spec/blob/master/Spec.md>`_ specification for on-the-wire / over-the-air encryption
+* Reticulum uses a modified version of the `Fernet <https://github.com/fernet/spec/blob/master/Spec.md>`_ specification for on-the-wire / over-the-air encryption
 
-  * All keys are ephemeral and derived from an ECDH key exchange on Curve25519
+  * Keys are ephemeral and derived from an ECDH key exchange on Curve25519
 
   * AES-128 in CBC mode with PKCS7 padding
 
@@ -63,6 +63,8 @@ What does Reticulum Offer?
 
   * IVs are generated through os.urandom()
 
+  * No Version and Timestamp metadata included
+
 * Unforgeable packet delivery confirmations
 
 * A variety of supported interface types
@@ -99,7 +101,8 @@ of the types of interfaces Reticulum was designed for.
 An open-source LoRa-based interface called `RNode <https://unsigned.io/rnode>`_
 has been designed as an example transceiver that is very suitable for
 Reticulum. It is possible to build it yourself, to transform a common LoRa
-development board into one, or it can be purchased as a complete transceiver.
+development board into one, or it can be purchased as a complete transceiver
+from various vendors.
 
 Reticulum can also be encapsulated over existing IP networks, so there's
 nothing stopping you from using it over wired Ethernet or your local WiFi

docs/manual/_static/documentation_options.js

@@ -1,6 +1,6 @@
 var DOCUMENTATION_OPTIONS = {
     URL_ROOT: document.getElementById("documentation_options").getAttribute('data-url_root'),
-    VERSION: '0.7.6 beta',
+    VERSION: '0.7.7 beta',
     LANGUAGE: 'en',
     COLLAPSE_INDEX: false,
     BUILDER: 'html',

docs/manual/examples.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Support Reticulum" href="support.html" /><link rel="prev" title="Building Networks" href="networks.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Code Examples - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Code Examples - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">
@@ -656,7 +656,6 @@ the Packet interface.</p>
 <span class="c1"># of the packet.                                         #</span>
 <span class="c1">##########################################################</span>
 
-<span class="kn">import</span> <span class="nn">os</span>
 <span class="kn">import</span> <span class="nn">argparse</span>
 <span class="kn">import</span> <span class="nn">RNS</span>
 
@@ -679,19 +678,8 @@ the Packet interface.</p>
     <span class="c1"># We must first initialise Reticulum</span>
     <span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
     
-    <span class="c1"># Load identity from file if it exist or randomley create</span>
-    <span class="k">if</span> <span class="n">configpath</span><span class="p">:</span>
-        <span class="n">ifilepath</span> <span class="o">=</span> <span class="s2">&quot;</span><span class="si">%s</span><span class="s2">/storage/identitiesy/</span><span class="si">%s</span><span class="s2">&quot;</span> <span class="o">%</span> <span class="p">(</span><span class="n">configpath</span><span class="p">,</span><span class="n">APP_NAME</span><span class="p">)</span>
-    <span class="k">else</span><span class="p">:</span>
-        <span class="n">ifilepath</span> <span class="o">=</span> <span class="s2">&quot;</span><span class="si">%s</span><span class="s2">/storage/identities/</span><span class="si">%s</span><span class="s2">&quot;</span> <span class="o">%</span> <span class="p">(</span><span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="o">.</span><span class="n">configdir</span><span class="p">,</span><span class="n">APP_NAME</span><span class="p">)</span>
-    <span class="k">if</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">exists</span><span class="p">(</span><span class="n">ifilepath</span><span class="p">):</span>
-        <span class="c1"># Load identity from file</span>
-        <span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="o">.</span><span class="n">from_file</span><span class="p">(</span><span class="n">ifilepath</span><span class="p">)</span>
-        <span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;loaded identity from file: &quot;</span><span class="o">+</span><span class="n">ifilepath</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_VERBOSE</span><span class="p">)</span>
-    <span class="k">else</span><span class="p">:</span>
-        <span class="c1"># Randomly create a new identity for our echo example</span>
-        <span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
-        <span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;created new identity&quot;</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_VERBOSE</span><span class="p">)</span>
+    <span class="c1"># Randomly create a new identity for our echo server</span>
+    <span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
 
     <span class="c1"># We create a destination that clients can query. We want</span>
     <span class="c1"># to be able to verify echo replies to our clients, so we</span>
@@ -1030,8 +1018,8 @@ destination, and passing traffic back and forth over the link.</p>
     <span class="c1"># We must first initialise Reticulum</span>
     <span class="n">reticulum</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Reticulum</span><span class="p">(</span><span class="n">configpath</span><span class="p">)</span>
     
+    <span class="c1"># Randomly create a new identity for our link example</span>
     <span class="n">server_identity</span> <span class="o">=</span> <span class="n">RNS</span><span class="o">.</span><span class="n">Identity</span><span class="p">()</span>
-    <span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;created new identity&quot;</span><span class="p">,</span> <span class="n">RNS</span><span class="o">.</span><span class="n">LOG_VERBOSE</span><span class="p">)</span>
 
     <span class="c1"># We create a destination that clients can connect to. We</span>
     <span class="c1"># want clients to create links to this destination, so we</span>
@@ -1060,7 +1048,7 @@ destination, and passing traffic back and forth over the link.</p>
         <span class="s2">&quot; running, waiting for a connection.&quot;</span>
     <span class="p">)</span>
 
-    <span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Hit enter to manually send an announce (Ctrl-C or </span><span class="se">\&quot;</span><span class="s2">quit</span><span class="se">\&quot;</span><span class="s2"> to quit)&quot;</span><span class="p">)</span>
+    <span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Hit enter to manually send an announce (Ctrl-C to quit)&quot;</span><span class="p">)</span>
 
     <span class="c1"># We enter a loop that runs until the users exits.</span>
     <span class="c1"># If the user hits enter, we will announce our server</span>
@@ -1070,12 +1058,6 @@ destination, and passing traffic back and forth over the link.</p>
         <span class="n">entered</span> <span class="o">=</span> <span class="nb">input</span><span class="p">()</span>
         <span class="n">destination</span><span class="o">.</span><span class="n">announce</span><span class="p">()</span>
         <span class="n">RNS</span><span class="o">.</span><span class="n">log</span><span class="p">(</span><span class="s2">&quot;Sent announce from &quot;</span><span class="o">+</span><span class="n">RNS</span><span class="o">.</span><span class="n">prettyhexrep</span><span class="p">(</span><span class="n">destination</span><span class="o">.</span><span class="n">hash</span><span class="p">))</span>
-        <span class="k">if</span> <span class="n">entered</span> <span class="o">==</span> <span class="s2">&quot;quit&quot;</span><span class="p">:</span>
-            <span class="k">if</span> <span class="n">latest_client_link</span><span class="p">:</span>
-                <span class="n">latest_client_link</span><span class="o">.</span><span class="n">teardown</span><span class="p">()</span>
-            <span class="k">break</span>
-    <span class="nb">print</span><span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">)</span>
-    <span class="n">exit</span><span class="p">()</span>
 
 <span class="c1"># When a client establishes a link to our server</span>
 <span class="c1"># destination, this function will be called with</span>

docs/manual/forhumans.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>An Explanation of Reticulum for Human Beings - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>An Explanation of Reticulum for Human Beings - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/genindex.html

@@ -4,7 +4,7 @@
     <meta name="viewport" content="width=device-width,initial-scale=1"/>
     <meta name="color-scheme" content="light dark"><link rel="index" title="Index" href="#" /><link rel="search" title="Search" href="search.html" />
 
-    <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/><title>Index - Reticulum Network Stack 0.7.6 beta documentation</title>
+    <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/><title>Index - Reticulum Network Stack 0.7.7 beta documentation</title>
 <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -139,7 +139,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -165,7 +165,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">
@@ -330,6 +330,8 @@
   <h2>E</h2>
   <table style="width: 100%" class="indextable genindextable"><tr>
     <td style="width: 33%; vertical-align: top;"><ul>
+        <li><a href="reference.html#RNS.Destination.enable_ratchets">enable_ratchets() (RNS.Destination method)</a>
+</li>
         <li><a href="reference.html#RNS.Destination.encrypt">encrypt() (RNS.Destination method)</a>
 
         <ul>
@@ -339,6 +341,8 @@
     </ul></td>
     <td style="width: 33%; vertical-align: top;"><ul>
         <li><a href="reference.html#RNS.Packet.ENCRYPTED_MDU">ENCRYPTED_MDU (RNS.Packet attribute)</a>
+</li>
+        <li><a href="reference.html#RNS.Destination.enforce_ratchets">enforce_ratchets() (RNS.Destination method)</a>
 </li>
         <li><a href="reference.html#RNS.Link.ESTABLISHMENT_TIMEOUT_PER_HOP">ESTABLISHMENT_TIMEOUT_PER_HOP (RNS.Link attribute)</a>
 </li>
@@ -568,6 +572,14 @@
   <h2>R</h2>
   <table style="width: 100%" class="indextable genindextable"><tr>
     <td style="width: 33%; vertical-align: top;"><ul>
+        <li><a href="reference.html#RNS.Destination.RATCHET_COUNT">RATCHET_COUNT (RNS.Destination attribute)</a>
+</li>
+        <li><a href="reference.html#RNS.Identity.RATCHET_EXPIRY">RATCHET_EXPIRY (RNS.Identity attribute)</a>
+</li>
+        <li><a href="reference.html#RNS.Destination.RATCHET_INTERVAL">RATCHET_INTERVAL (RNS.Destination attribute)</a>
+</li>
+        <li><a href="reference.html#RNS.Identity.RATCHETSIZE">RATCHETSIZE (RNS.Identity attribute)</a>
+</li>
         <li><a href="reference.html#RNS.RawChannelReader">RawChannelReader (class in RNS)</a>
 </li>
         <li><a href="reference.html#RNS.RawChannelWriter">RawChannelWriter (class in RNS)</a>
@@ -580,12 +592,12 @@
 </li>
         <li><a href="reference.html#RNS.Channel.Channel.register_message_type">register_message_type() (RNS.Channel.Channel method)</a>
 </li>
+    </ul></td>
+    <td style="width: 33%; vertical-align: top;"><ul>
         <li><a href="reference.html#RNS.Destination.register_request_handler">register_request_handler() (RNS.Destination method)</a>
 </li>
         <li><a href="reference.html#RNS.Reticulum.remote_management_enabled">remote_management_enabled() (RNS.Reticulum static method)</a>
 </li>
-    </ul></td>
-    <td style="width: 33%; vertical-align: top;"><ul>
         <li><a href="reference.html#RNS.Channel.Channel.remove_message_handler">remove_message_handler() (RNS.Channel.Channel method)</a>
 </li>
         <li><a href="reference.html#RNS.RawChannelReader.remove_ready_callback">remove_ready_callback() (RNS.RawChannelReader method)</a>
@@ -633,6 +645,8 @@
         <li><a href="reference.html#RNS.Destination.set_proof_requested_callback">set_proof_requested_callback() (RNS.Destination method)</a>
 </li>
         <li><a href="reference.html#RNS.Destination.set_proof_strategy">set_proof_strategy() (RNS.Destination method)</a>
+</li>
+        <li><a href="reference.html#RNS.Destination.set_ratchet_interval">set_ratchet_interval() (RNS.Destination method)</a>
 </li>
         <li><a href="reference.html#RNS.Link.set_remote_identified_callback">set_remote_identified_callback() (RNS.Link method)</a>
 </li>
@@ -645,6 +659,8 @@
         <li><a href="reference.html#RNS.Link.set_resource_started_callback">set_resource_started_callback() (RNS.Link method)</a>
 </li>
         <li><a href="reference.html#RNS.Link.set_resource_strategy">set_resource_strategy() (RNS.Link method)</a>
+</li>
+        <li><a href="reference.html#RNS.Destination.set_retained_ratchets">set_retained_ratchets() (RNS.Destination method)</a>
 </li>
         <li><a href="reference.html#RNS.PacketReceipt.set_timeout">set_timeout() (RNS.PacketReceipt method)</a>
 </li>

docs/manual/gettingstartedfast.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Using Reticulum on Your System" href="using.html" /><link rel="prev" title="What is Reticulum?" href="whatis.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Getting Started Fast - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Getting Started Fast - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/hardware.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Configuring Interfaces" href="interfaces.html" /><link rel="prev" title="Understanding Reticulum" href="understanding.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Communications Hardware - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Communications Hardware - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/index.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="What is Reticulum?" href="whatis.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="#"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="#"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/interfaces.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Building Networks" href="networks.html" /><link rel="prev" title="Communications Hardware" href="hardware.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Configuring Interfaces - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Configuring Interfaces - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/networks.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Code Examples" href="examples.html" /><link rel="prev" title="Configuring Interfaces" href="interfaces.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Building Networks - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Building Networks - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/reference.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="prev" title="Support Reticulum" href="support.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>API Reference - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>API Reference - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">
@@ -356,7 +356,21 @@ for all encrypted communication over Reticulum networks.</p>
 <dl class="py attribute">
 <dt class="sig sig-object py" id="RNS.Identity.KEYSIZE">
 <span class="sig-name descname"><span class="pre">KEYSIZE</span></span><em class="property"><span class="w"> </span><span class="p"><span class="pre">=</span></span><span class="w"> </span><span class="pre">512</span></em><a class="headerlink" href="#RNS.Identity.KEYSIZE" title="Permalink to this definition">#</a></dt>
-<dd><p>X25519 key size in bits. A complete key is the concatenation of a 256 bit encryption key, and a 256 bit signing key.</p>
+<dd><p>X.25519 key size in bits. A complete key is the concatenation of a 256 bit encryption key, and a 256 bit signing key.</p>
+</dd></dl>
+
+<dl class="py attribute">
+<dt class="sig sig-object py" id="RNS.Identity.RATCHETSIZE">
+<span class="sig-name descname"><span class="pre">RATCHETSIZE</span></span><em class="property"><span class="w"> </span><span class="p"><span class="pre">=</span></span><span class="w"> </span><span class="pre">256</span></em><a class="headerlink" href="#RNS.Identity.RATCHETSIZE" title="Permalink to this definition">#</a></dt>
+<dd><p>X.25519 ratchet key size in bits.</p>
+</dd></dl>
+
+<dl class="py attribute">
+<dt class="sig sig-object py" id="RNS.Identity.RATCHET_EXPIRY">
+<span class="sig-name descname"><span class="pre">RATCHET_EXPIRY</span></span><em class="property"><span class="w"> </span><span class="p"><span class="pre">=</span></span><span class="w"> </span><span class="pre">2592000</span></em><a class="headerlink" href="#RNS.Identity.RATCHET_EXPIRY" title="Permalink to this definition">#</a></dt>
+<dd><p>The expiry time for received ratchets in seconds, defaults to 30 days. Reticulum will always use the most recently
+announced ratchet, and remember it for up to <code class="docutils literal notranslate"><span class="pre">RATCHET_EXPIRY</span></code> since receiving it, after which it will be discarded.
+If a newer ratchet is announced in the meantime, it will be replace the already known ratchet.</p>
 </dd></dl>
 
 <dl class="py attribute">
@@ -532,7 +546,7 @@ communication for the identity. Be very careful with this method.</p>
 
 <dl class="py method">
 <dt class="sig sig-object py" id="RNS.Identity.encrypt">
-<span class="sig-name descname"><span class="pre">encrypt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">plaintext</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Identity.encrypt" title="Permalink to this definition">#</a></dt>
+<span class="sig-name descname"><span class="pre">encrypt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">plaintext</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ratchet</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Identity.encrypt" title="Permalink to this definition">#</a></dt>
 <dd><p>Encrypts information for the identity.</p>
 <dl class="field-list simple">
 <dt class="field-odd">Parameters<span class="colon">:</span></dt>
@@ -549,7 +563,7 @@ communication for the identity. Be very careful with this method.</p>
 
 <dl class="py method">
 <dt class="sig sig-object py" id="RNS.Identity.decrypt">
-<span class="sig-name descname"><span class="pre">decrypt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">ciphertext_token</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Identity.decrypt" title="Permalink to this definition">#</a></dt>
+<span class="sig-name descname"><span class="pre">decrypt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">ciphertext_token</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ratchets</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">enforce_ratchets</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Identity.decrypt" title="Permalink to this definition">#</a></dt>
 <dd><p>Decrypts information for the identity.</p>
 <dl class="field-list simple">
 <dt class="field-odd">Parameters<span class="colon">:</span></dt>
@@ -611,7 +625,7 @@ communication for the identity. Be very careful with this method.</p>
 instances are used both to create outgoing and incoming endpoints. The
 destination type will decide if encryption, and what type, is used in
 communication with the endpoint. A destination can also announce its
-presence on the network, which will also distribute necessary keys for
+presence on the network, which will distribute necessary keys for
 encrypted communication with it.</p>
 <dl class="field-list simple">
 <dt class="field-odd">Parameters<span class="colon">:</span></dt>
@@ -624,6 +638,18 @@ encrypted communication with it.</p>
 </ul>
 </dd>
 </dl>
+<dl class="py attribute">
+<dt class="sig sig-object py" id="RNS.Destination.RATCHET_COUNT">
+<span class="sig-name descname"><span class="pre">RATCHET_COUNT</span></span><em class="property"><span class="w"> </span><span class="p"><span class="pre">=</span></span><span class="w"> </span><span class="pre">512</span></em><a class="headerlink" href="#RNS.Destination.RATCHET_COUNT" title="Permalink to this definition">#</a></dt>
+<dd><p>The default number of generated ratchet keys a destination will retain, if it has ratchets enabled.</p>
+</dd></dl>
+
+<dl class="py attribute">
+<dt class="sig sig-object py" id="RNS.Destination.RATCHET_INTERVAL">
+<span class="sig-name descname"><span class="pre">RATCHET_INTERVAL</span></span><em class="property"><span class="w"> </span><span class="p"><span class="pre">=</span></span><span class="w"> </span><span class="pre">1800</span></em><a class="headerlink" href="#RNS.Destination.RATCHET_INTERVAL" title="Permalink to this definition">#</a></dt>
+<dd><p>The minimum interval between rotating ratchet keys, in seconds.</p>
+</dd></dl>
+
 <dl class="py method">
 <dt class="sig sig-object py" id="RNS.Destination.expand_name">
 <em class="property"><span class="pre">static</span><span class="w"> </span></em><span class="sig-name descname"><span class="pre">expand_name</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">identity</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">app_name</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span><span class="n"><span class="pre">aspects</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Destination.expand_name" title="Permalink to this definition">#</a></dt>
@@ -774,6 +800,64 @@ proofs should be returned for received packets.</p>
 </dl>
 </dd></dl>
 
+<dl class="py method">
+<dt class="sig sig-object py" id="RNS.Destination.enable_ratchets">
+<span class="sig-name descname"><span class="pre">enable_ratchets</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">ratchets_path</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Destination.enable_ratchets" title="Permalink to this definition">#</a></dt>
+<dd><p>Enables ratchets on the destination. When ratchets are enabled, Reticulum will automatically rotate
+the keys used to encrypt packets to this destination, and include the latest ratchet key in announces.</p>
+<p>Enabling ratchets on a destination will provide forward secrecy for packets sent to that destination,
+even when sent outside a <code class="docutils literal notranslate"><span class="pre">Link</span></code>. The normal Reticulum <code class="docutils literal notranslate"><span class="pre">Link</span></code> establishment procedure already performs
+its own ephemeral key exchange for each link establishment, which means that ratchets are not necessary
+to provide forward secrecy for links.</p>
+<p>Enabling ratchets will have a small impact on announce size, adding 32 bytes to every sent announce.</p>
+<dl class="field-list simple">
+<dt class="field-odd">Parameters<span class="colon">:</span></dt>
+<dd class="field-odd"><p><strong>ratchets_path</strong> – The path to a file to store ratchet data in.</p>
+</dd>
+<dt class="field-even">Returns<span class="colon">:</span></dt>
+<dd class="field-even"><p>True if the operation succeeded, otherwise False.</p>
+</dd>
+</dl>
+</dd></dl>
+
+<dl class="py method">
+<dt class="sig sig-object py" id="RNS.Destination.enforce_ratchets">
+<span class="sig-name descname"><span class="pre">enforce_ratchets</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Destination.enforce_ratchets" title="Permalink to this definition">#</a></dt>
+<dd><p>When ratchet enforcement is enabled, this destination will never accept packets that use its
+base Identity key for encryption, but only accept packets encrypted with one of the retained
+ratchet keys.</p>
+</dd></dl>
+
+<dl class="py method">
+<dt class="sig sig-object py" id="RNS.Destination.set_retained_ratchets">
+<span class="sig-name descname"><span class="pre">set_retained_ratchets</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">retained_ratchets</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Destination.set_retained_ratchets" title="Permalink to this definition">#</a></dt>
+<dd><p>Sets the number of previously generated ratchet keys this destination will retain,
+and try to use when decrypting incoming packets. Defaults to <code class="docutils literal notranslate"><span class="pre">Destination.RATCHET_COUNT</span></code>.</p>
+<dl class="field-list simple">
+<dt class="field-odd">Parameters<span class="colon">:</span></dt>
+<dd class="field-odd"><p><strong>retained_ratchets</strong> – The number of generated ratchets to retain.</p>
+</dd>
+<dt class="field-even">Returns<span class="colon">:</span></dt>
+<dd class="field-even"><p>True if the operation succeeded, False if not.</p>
+</dd>
+</dl>
+</dd></dl>
+
+<dl class="py method">
+<dt class="sig sig-object py" id="RNS.Destination.set_ratchet_interval">
+<span class="sig-name descname"><span class="pre">set_ratchet_interval</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">interval</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Destination.set_ratchet_interval" title="Permalink to this definition">#</a></dt>
+<dd><p>Sets the minimum interval in seconds between ratchet key rotation.
+Defaults to <code class="docutils literal notranslate"><span class="pre">Destination.RATCHET_INTERVAL</span></code>.</p>
+<dl class="field-list simple">
+<dt class="field-odd">Parameters<span class="colon">:</span></dt>
+<dd class="field-odd"><p><strong>interval</strong> – The minimum interval in seconds.</p>
+</dd>
+<dt class="field-even">Returns<span class="colon">:</span></dt>
+<dd class="field-even"><p>True if the operation succeeded, False if not.</p>
+</dd>
+</dl>
+</dd></dl>
+
 <dl class="py method">
 <dt class="sig sig-object py" id="RNS.Destination.create_keys">
 <span class="sig-name descname"><span class="pre">create_keys</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#RNS.Destination.create_keys" title="Permalink to this definition">#</a></dt>
@@ -1964,6 +2048,8 @@ will announce it.</p>
 <li><a class="reference internal" href="#RNS.Identity"><code class="docutils literal notranslate"><span class="pre">Identity</span></code></a><ul>
 <li><a class="reference internal" href="#RNS.Identity.CURVE"><code class="docutils literal notranslate"><span class="pre">CURVE</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Identity.KEYSIZE"><code class="docutils literal notranslate"><span class="pre">KEYSIZE</span></code></a></li>
+<li><a class="reference internal" href="#RNS.Identity.RATCHETSIZE"><code class="docutils literal notranslate"><span class="pre">RATCHETSIZE</span></code></a></li>
+<li><a class="reference internal" href="#RNS.Identity.RATCHET_EXPIRY"><code class="docutils literal notranslate"><span class="pre">RATCHET_EXPIRY</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Identity.TRUNCATED_HASHLENGTH"><code class="docutils literal notranslate"><span class="pre">TRUNCATED_HASHLENGTH</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Identity.recall"><code class="docutils literal notranslate"><span class="pre">recall()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Identity.recall_app_data"><code class="docutils literal notranslate"><span class="pre">recall_app_data()</span></code></a></li>
@@ -1984,6 +2070,8 @@ will announce it.</p>
 </ul>
 </li>
 <li><a class="reference internal" href="#RNS.Destination"><code class="docutils literal notranslate"><span class="pre">Destination</span></code></a><ul>
+<li><a class="reference internal" href="#RNS.Destination.RATCHET_COUNT"><code class="docutils literal notranslate"><span class="pre">RATCHET_COUNT</span></code></a></li>
+<li><a class="reference internal" href="#RNS.Destination.RATCHET_INTERVAL"><code class="docutils literal notranslate"><span class="pre">RATCHET_INTERVAL</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.expand_name"><code class="docutils literal notranslate"><span class="pre">expand_name()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.app_and_aspects_from_name"><code class="docutils literal notranslate"><span class="pre">app_and_aspects_from_name()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.hash_from_name_and_identity"><code class="docutils literal notranslate"><span class="pre">hash_from_name_and_identity()</span></code></a></li>
@@ -1996,6 +2084,10 @@ will announce it.</p>
 <li><a class="reference internal" href="#RNS.Destination.set_proof_strategy"><code class="docutils literal notranslate"><span class="pre">set_proof_strategy()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.register_request_handler"><code class="docutils literal notranslate"><span class="pre">register_request_handler()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.deregister_request_handler"><code class="docutils literal notranslate"><span class="pre">deregister_request_handler()</span></code></a></li>
+<li><a class="reference internal" href="#RNS.Destination.enable_ratchets"><code class="docutils literal notranslate"><span class="pre">enable_ratchets()</span></code></a></li>
+<li><a class="reference internal" href="#RNS.Destination.enforce_ratchets"><code class="docutils literal notranslate"><span class="pre">enforce_ratchets()</span></code></a></li>
+<li><a class="reference internal" href="#RNS.Destination.set_retained_ratchets"><code class="docutils literal notranslate"><span class="pre">set_retained_ratchets()</span></code></a></li>
+<li><a class="reference internal" href="#RNS.Destination.set_ratchet_interval"><code class="docutils literal notranslate"><span class="pre">set_ratchet_interval()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.create_keys"><code class="docutils literal notranslate"><span class="pre">create_keys()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.get_private_key"><code class="docutils literal notranslate"><span class="pre">get_private_key()</span></code></a></li>
 <li><a class="reference internal" href="#RNS.Destination.load_private_key"><code class="docutils literal notranslate"><span class="pre">load_private_key()</span></code></a></li>

docs/manual/search.html

@@ -4,7 +4,7 @@
     <meta name="viewport" content="width=device-width,initial-scale=1"/>
     <meta name="color-scheme" content="light dark"><link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="#" />
 
-    <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/><title>Search - Reticulum Network Stack 0.7.6 beta documentation</title><link rel="stylesheet" type="text/css" href="_static/pygments.css" />
+    <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/><title>Search - Reticulum Network Stack 0.7.7 beta documentation</title><link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo-extensions.css?digest=30d1aed668e5c3a91c3e3bf6a60b675221979f0e" />
@@ -138,7 +138,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -164,7 +164,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="#" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/support.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="API Reference" href="reference.html" /><link rel="prev" title="Code Examples" href="examples.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Support Reticulum - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Support Reticulum - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/understanding.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Communications Hardware" href="hardware.html" /><link rel="prev" title="Using Reticulum on Your System" href="using.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Understanding Reticulum - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Understanding Reticulum - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">
@@ -360,10 +360,11 @@ be sufficient, even far into the future.</p>
 <p>By default Reticulum encrypts all data using elliptic curve cryptography and AES. Any packet sent to a
 destination is encrypted with a per-packet derived key. Reticulum can also set up an encrypted
 channel to a destination, called a <em>Link</em>. Both data sent over Links and single packets offer
-<em>Initiator Anonymity</em>, and links additionally offer <em>Forward Secrecy</em> by using an Elliptic Curve
-Diffie Hellman key exchange on Curve25519 to derive per-link ephemeral keys. The multi-hop transport,
-coordination, verification and reliability layers are fully autonomous and also based on elliptic
-curve cryptography.</p>
+<em>Initiator Anonymity</em>. Links additionally offer <em>Forward Secrecy</em> by default, employing an Elliptic Curve
+Diffie Hellman key exchange on Curve25519 to derive per-link ephemeral keys. Asymmetric, link-less
+packet communication can also provide forward secrecy, with automatic key ratcheting, by enabling
+ratchets on a per-destination basis. The multi-hop transport, coordination, verification and reliability
+layers are fully autonomous and also based on elliptic curve cryptography.</p>
 <p>Reticulum also offers symmetric key encryption for group-oriented communications, as well as
 unencrypted packets for local broadcast purposes.</p>
 <p>Reticulum can connect to a variety of interfaces such as radio modems, data radios and serial ports,
@@ -639,7 +640,7 @@ expect. Reticulum offers two ways to do this.</p>
 <li><div class="line-block">
 <div class="line">A packet is always created with an associated destination and some payload data. When the packet is sent
 to a <em>single</em> destination type, Reticulum will automatically create an ephemeral encryption key, perform
-an ECDH key exchange with the destination’s public key, and encrypt the information.</div>
+an ECDH key exchange with the destination’s public key (or ratchet key, if available), and encrypt the information.</div>
 </div>
 </li>
 <li><div class="line-block">
@@ -927,7 +928,8 @@ A Reticulum packet is composed of the following fields:
 [HEADER 2 bytes] [ADDRESSES 16/32 bytes] [CONTEXT 1 byte] [DATA 0-465 bytes]
 
 * The HEADER field is 2 bytes long.
-  * Byte 1: [IFAC Flag], [Header Type], [Propagation Type], [Destination Type] and [Packet Type]
+  * Byte 1: [IFAC Flag], [Header Type], [Context Flag], [Propagation Type],
+            [Destination Type] and [Packet Type]
   * Byte 2: Number of hops
 
 * Interface Access Code field if the IFAC flag was set.
@@ -959,12 +961,16 @@ type 1           0  Two byte header, one 16 byte address field
 type 2           1  Two byte header, two 16 byte address fields
 
 
+Context Flag
+-----------------
+unset            0  The context flag is used for various types
+set              1  of signalling, depending on packet context
+
+
 Propagation Types
 -----------------
-broadcast       00
-transport       01
-reserved        10
-reserved        11
+broadcast        0
+transport        1
 
 
 Destination Types
@@ -1063,10 +1069,11 @@ both on general-purpose CPUs and on microcontrollers. The necessary primitives a
 <li><p>Ed25519 for signatures</p></li>
 <li><p>X25519 for ECDH key exchanges</p></li>
 <li><p>HKDF for key derivation</p></li>
-<li><p>Fernet for encrypted tokens</p>
+<li><p>Modified Fernet for encrypted tokens</p>
 <ul>
 <li><p>AES-128 in CBC mode</p></li>
 <li><p>HMAC for message authentication</p></li>
+<li><p>No Version and Timestamp metadata included</p></li>
 </ul>
 </li>
 <li><p>SHA-256</p></li>

docs/manual/using.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Understanding Reticulum" href="understanding.html" /><link rel="prev" title="Getting Started Fast" href="gettingstartedfast.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>Using Reticulum on Your System - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>Using Reticulum on Your System - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">

docs/manual/whatis.html

@@ -6,7 +6,7 @@
 <link rel="index" title="Index" href="genindex.html" /><link rel="search" title="Search" href="search.html" /><link rel="next" title="Getting Started Fast" href="gettingstartedfast.html" /><link rel="prev" title="Reticulum Network Stack Manual" href="index.html" />
 
     <meta name="generator" content="sphinx-5.3.0, furo 2022.09.29.dev1"/>
-        <title>What is Reticulum? - Reticulum Network Stack 0.7.6 beta documentation</title>
+        <title>What is Reticulum? - Reticulum Network Stack 0.7.7 beta documentation</title>
       <link rel="stylesheet" type="text/css" href="_static/pygments.css" />
     <link rel="stylesheet" type="text/css" href="_static/styles/furo.css?digest=189ec851f9bb375a2509b67be1f64f0cf212b702" />
     <link rel="stylesheet" type="text/css" href="_static/copybutton.css" />
@@ -141,7 +141,7 @@
       </label>
     </div>
     <div class="header-center">
-      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.6 beta documentation</div></a>
+      <a href="index.html"><div class="brand">Reticulum Network Stack 0.7.7 beta documentation</div></a>
     </div>
     <div class="header-right">
       <div class="theme-toggle-container theme-toggle-header">
@@ -167,7 +167,7 @@
     <img class="sidebar-logo" src="_static/rns_logo_512.png" alt="Logo"/>
   </div>
   
-  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.6 beta documentation</span>
+  <span class="sidebar-brand-text">Reticulum Network Stack 0.7.7 beta documentation</span>
   
 </a><form class="sidebar-search-container" method="get" action="search.html" role="search">
   <input class="sidebar-search" placeholder="Search" name="q" aria-label="Search">
@@ -262,12 +262,13 @@ considered complete and stable at the moment, but could change if absolutely war
 <li><p>Complete initiator anonymity, communicate without revealing your identity</p></li>
 <li><p>Asymmetric encryption based on X25519, and Ed25519 signatures as a basis for all communication</p></li>
 <li><p>Forward Secrecy by using ephemeral Elliptic Curve Diffie-Hellman keys on Curve25519</p></li>
-<li><p>Reticulum uses the <a class="reference external" href="https://github.com/fernet/spec/blob/master/Spec.md">Fernet</a> specification for on-the-wire / over-the-air encryption</p>
+<li><p>Reticulum uses a modified version of the <a class="reference external" href="https://github.com/fernet/spec/blob/master/Spec.md">Fernet</a> specification for on-the-wire / over-the-air encryption</p>
 <ul>
-<li><p>All keys are ephemeral and derived from an ECDH key exchange on Curve25519</p></li>
+<li><p>Keys are ephemeral and derived from an ECDH key exchange on Curve25519</p></li>
 <li><p>AES-128 in CBC mode with PKCS7 padding</p></li>
 <li><p>HMAC using SHA256 for authentication</p></li>
 <li><p>IVs are generated through os.urandom()</p></li>
+<li><p>No Version and Timestamp metadata included</p></li>
 </ul>
 </li>
 <li><p>Unforgeable packet delivery confirmations</p></li>
@@ -300,7 +301,8 @@ of the types of interfaces Reticulum was designed for.</p>
 <p>An open-source LoRa-based interface called <a class="reference external" href="https://unsigned.io/rnode">RNode</a>
 has been designed as an example transceiver that is very suitable for
 Reticulum. It is possible to build it yourself, to transform a common LoRa
-development board into one, or it can be purchased as a complete transceiver.</p>
+development board into one, or it can be purchased as a complete transceiver
+from various vendors.</p>
 <p>Reticulum can also be encapsulated over existing IP networks, so there’s
 nothing stopping you from using it over wired Ethernet or your local WiFi
 network, where it’ll work just as well. In fact, one of the strengths of

docs/source/understanding.rst

@@ -134,10 +134,11 @@ be sufficient, even far into the future.
 By default Reticulum encrypts all data using elliptic curve cryptography and AES. Any packet sent to a
 destination is encrypted with a per-packet derived key. Reticulum can also set up an encrypted
 channel to a destination, called a *Link*. Both data sent over Links and single packets offer
-*Initiator Anonymity*, and links additionally offer *Forward Secrecy* by using an Elliptic Curve
-Diffie Hellman key exchange on Curve25519 to derive per-link ephemeral keys. The multi-hop transport,
-coordination, verification and reliability layers are fully autonomous and also based on elliptic
-curve cryptography.
+*Initiator Anonymity*. Links additionally offer *Forward Secrecy* by default, employing an Elliptic Curve
+Diffie Hellman key exchange on Curve25519 to derive per-link ephemeral keys. Asymmetric, link-less
+packet communication can also provide forward secrecy, with automatic key ratcheting, by enabling
+ratchets on a per-destination basis. The multi-hop transport, coordination, verification and reliability
+layers are fully autonomous and also based on elliptic curve cryptography.
 
 Reticulum also offers symmetric key encryption for group-oriented communications, as well as
 unencrypted packets for local broadcast purposes.
@@ -431,7 +432,7 @@ For exchanges of small amounts of information, Reticulum offers the *Packet* API
 
 * | A packet is always created with an associated destination and some payload data. When the packet is sent
     to a *single* destination type, Reticulum will automatically create an ephemeral encryption key, perform
-    an ECDH key exchange with the destination's public key, and encrypt the information.
+    an ECDH key exchange with the destination's public key (or ratchet key, if available), and encrypt the information.
 
 * | It is important to note that this key exchange does not require any network traffic. The sender already
     knows the public key of the destination from an earlier received *announce*, and can thus perform the ECDH
@@ -693,7 +694,8 @@ Wire Format
     [HEADER 2 bytes] [ADDRESSES 16/32 bytes] [CONTEXT 1 byte] [DATA 0-465 bytes]
 
     * The HEADER field is 2 bytes long.
-      * Byte 1: [IFAC Flag], [Header Type], [Propagation Type], [Destination Type] and [Packet Type]
+      * Byte 1: [IFAC Flag], [Header Type], [Context Flag], [Propagation Type],
+                [Destination Type] and [Packet Type]
       * Byte 2: Number of hops
 
     * Interface Access Code field if the IFAC flag was set.
@@ -725,12 +727,16 @@ Wire Format
     type 2           1  Two byte header, two 16 byte address fields
 
 
+    Context Flag
+    -----------------
+    unset            0  The context flag is used for various types
+    set              1  of signalling, depending on packet context
+
+
     Propagation Types
     -----------------
-    broadcast       00
-    transport       01
-    reserved        10
-    reserved        11
+    broadcast        0
+    transport        1
 
 
     Destination Types
@@ -862,12 +868,14 @@ both on general-purpose CPUs and on microcontrollers. The necessary primitives a
 
 * HKDF for key derivation
 
-* Fernet for encrypted tokens
+* Modified Fernet for encrypted tokens
 
   * AES-128 in CBC mode
 
   * HMAC for message authentication
 
+  * No Version and Timestamp metadata included
+
 * SHA-256
 
 * SHA-512

docs/source/whatis.rst

@@ -53,9 +53,9 @@ What does Reticulum Offer?
 
 * Forward Secrecy by using ephemeral Elliptic Curve Diffie-Hellman keys on Curve25519
 
-* Reticulum uses the `Fernet <https://github.com/fernet/spec/blob/master/Spec.md>`_ specification for on-the-wire / over-the-air encryption
+* Reticulum uses a modified version of the `Fernet <https://github.com/fernet/spec/blob/master/Spec.md>`_ specification for on-the-wire / over-the-air encryption
 
-  * All keys are ephemeral and derived from an ECDH key exchange on Curve25519
+  * Keys are ephemeral and derived from an ECDH key exchange on Curve25519
 
   * AES-128 in CBC mode with PKCS7 padding
 
@@ -63,6 +63,8 @@ What does Reticulum Offer?
 
   * IVs are generated through os.urandom()
 
+  * No Version and Timestamp metadata included
+
 * Unforgeable packet delivery confirmations
 
 * A variety of supported interface types
@@ -99,7 +101,8 @@ of the types of interfaces Reticulum was designed for.
 An open-source LoRa-based interface called `RNode <https://unsigned.io/rnode>`_
 has been designed as an example transceiver that is very suitable for
 Reticulum. It is possible to build it yourself, to transform a common LoRa
-development board into one, or it can be purchased as a complete transceiver.
+development board into one, or it can be purchased as a complete transceiver
+from various vendors.
 
 Reticulum can also be encapsulated over existing IP networks, so there's
 nothing stopping you from using it over wired Ethernet or your local WiFi