Reticulum/FPE/Destination.py
2018-03-16 10:50:37 +01:00

229 lines
6.6 KiB
Python
Executable File

import base64
import math
from Identity import Identity
from Transport import Transport
from cryptography.fernet import Fernet
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives.asymmetric import padding
class Destination:
KEYSIZE = Identity.KEYSIZE;
PADDINGSIZE= Identity.PADDINGSIZE;
# Constants
SINGLE = 0x01;
GROUP = 0x02;
PLAIN = 0x03;
types = [SINGLE, GROUP, PLAIN]
IN = 0x11;
OUT = 0x12;
directions = [IN, OUT]
@staticmethod
def getDestinationName(app_name, *aspects):
# Check input values and build name string
if "." in app_name: raise ValueError("Dots can't be used in app names")
name = app_name
for aspect in aspects:
if "." in aspect: raise ValueError("Dots can't be used in aspects")
name = name + "." + aspect
return name
@staticmethod
def getDestinationHash(app_name, *aspects):
name = Destination.getDestinationName(app_name, *aspects)
# Create a digest for the destination
digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
digest.update(name)
return digest.finalize()[:10]
def __init__(self, direction, type, app_name, *aspects):
# Check input values and build name string
if "." in app_name: raise ValueError("Dots can't be used in app names")
if not type in Destination.types: raise ValueError("Unknown destination type")
if not direction in Destination.directions: raise ValueError("Unknown destination direction")
self.type = type
self.direction = direction
self.mtu = 0
self.name = Destination.getDestinationName(app_name, *aspects)
self.hash = Destination.getDestinationHash(app_name, *aspects)
self.hexhash = self.hash.encode("hex_codec")
self.callback = None
# Initialize keys to none
self.prv = None
self.pub = None
self.prv_bytes = None
self.pub_bytes = None
Transport.registerDestination(self)
def __str__(self):
return "<"+self.name+"/"+self.hexhash+">"
def setCallback(self, callback):
self.callback = callback
def receive(self, data):
plaintext = self.decrypt(data)
if plaintext != None and self.callback != None:
self.callback(plaintext, self)
def createKey(self):
if self.type == Destination.PLAIN:
raise TypeError("A plain destination does not hold any keys")
if self.type == Destination.SINGLE:
self.prv = rsa.generate_private_key(
public_exponent=65337,
key_size=Destination.KEYSIZE,
backend=default_backend()
)
self.prv_bytes = self.prv.private_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PrivateFormat.PKCS8,
encryption_algorithm=serialization.NoEncryption()
)
self.pub = self.prv.public_key()
self.pub_bytes = self.pub.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
print("Keys created, private length is "+str(len(self.prv_bytes)))
print("Keys created, public length is "+str(len(self.pub_bytes)))
#+", public length is "+str(len(self.pub_bytes))))
if self.type == Destination.GROUP:
self.prv_bytes = Fernet.generate_key()
self.prv = Fernet(self.prv_bytes)
def getKey(self):
if self.type == Destination.PLAIN:
raise TypeError("A plain destination does not hold any keys")
else:
return self.prv_bytes
def loadKey(self, key):
if self.type == Destination.PLAIN:
raise TypeError("A plain destination does not hold any keys")
if self.type == Destination.SINGLE:
self.prv_bytes = key
self.prv = serialization.load_der_private_key(self.prv_bytes, password=None,backend=default_backend())
self.pub = self.prv.public_key()
self.pub_bytes = self.pub.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
if self.type == Destination.GROUP:
self.prv_bytes = key
self.prv = Fernet(self.prv_bytes)
def loadPublicKey(self, key):
if self.type != Destination.SINGLE:
raise TypeError("Only the \"single\" destination type can hold a public key")
self.pub_bytes = key
self.pub = load_der_public_key(self.pub_bytes, backend=default_backend())
def encrypt(self, plaintext):
if self.type == Destination.PLAIN:
return plaintext
if self.type == Destination.SINGLE and self.prv != None:
chunksize = (Destination.KEYSIZE-Destination.PADDINGSIZE)/8
chunks = int(math.ceil(len(plaintext)/(float(chunksize))))
print("Plaintext size is "+str(len(plaintext))+", with "+str(chunks)+" chunks")
ciphertext = "";
for chunk in range(chunks):
start = chunk*chunksize
end = (chunk+1)*chunksize
if (chunk+1)*chunksize > len(plaintext):
end = len(plaintext)
print("Processing chunk "+str(chunk+1)+" of "+str(chunks)+". Starting at "+str(start)+" and stopping at "+str(end)+". The length is "+str(len(plaintext[start:end])))
ciphertext += self.pub.encrypt(
plaintext[start:end],
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA1()),
algorithm=hashes.SHA1(),
label=None
)
)
print("Plaintext encrypted, ciphertext length is "+str(len(ciphertext))+" bytes.")
return ciphertext
if self.type == Destination.GROUP and self.prv != None:
try:
return base64.urlsafe_b64decode(self.prv.encrypt(plaintext))
except:
return None
def decrypt(self, ciphertext):
if self.type == Destination.PLAIN:
return ciphertext
if self.type == Destination.SINGLE and self.prv != None:
print("Ciphertext length is "+str(len(ciphertext))+". ")
chunksize = (Destination.KEYSIZE)/8
chunks = int(math.ceil(len(ciphertext)/(float(chunksize))))
plaintext = "";
for chunk in range(chunks):
start = chunk*chunksize
end = (chunk+1)*chunksize
if (chunk+1)*chunksize > len(ciphertext):
end = len(ciphertext)
print("Processing chunk "+str(chunk+1)+" of "+str(chunks)+". Starting at "+str(start)+" and stopping at "+str(end)+". The length is "+str(len(ciphertext[start:end])))
plaintext += self.prv.decrypt(
ciphertext[start:end],
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA1()),
algorithm=hashes.SHA1(),
label=None
)
)
return plaintext;
if self.type == Destination.GROUP:
return self.prv.decrypt(base64.urlsafe_b64encode(ciphertext))
def sign(self, message):
if self.type == Destination.SINGLE and self.prv != None:
signer = self.prv.signer(
padding.PSS(
mgf=padding.MGF1(hashes.SHA256()),
salt_length=padding.PSS.MAX_LENGTH
),
hashes.SHA256()
)
signer.update(message)
return signer.finalize()
else:
return None