import base64 import math import FPE 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 = FPE.Identity.KEYSIZE; PADDINGSIZE= FPE.Identity.PADDINGSIZE; # Constants SINGLE = 0x00; GROUP = 0x01; PLAIN = 0x02; LINK = 0x03; types = [SINGLE, GROUP, PLAIN, LINK] 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, identity, 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 if identity == None: identity = Identity() identity.createKeys() self.identity = identity aspects = aspects+(identity.hexhash,) self.name = Destination.getDestinationName(app_name, *aspects) self.hash = Destination.getDestinationHash(app_name, *aspects) self.hexhash = self.hash.encode("hex_codec") self.callback = None FPE.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 createKeys(self): if self.type == Destination.PLAIN: raise TypeError("A plain destination does not hold any keys") if self.type == Destination.SINGLE: raise TypeError("A single destination holds keys through an Identity instance") if self.type == Destination.GROUP: self.prv_bytes = Fernet.generate_key() self.prv = Fernet(self.prv_bytes) def getPrivateKey(self): if self.type == Destination.PLAIN: raise TypeError("A plain destination does not hold any keys") elif self.type == Destination.SINGLE: raise TypeError("A single destination holds keys through an Identity instance") else: return self.prv_bytes def loadPrivateKey(self, key): if self.type == Destination.PLAIN: raise TypeError("A plain destination does not hold any keys") if self.type == Destination.SINGLE: raise TypeError("A single destination holds keys through an Identity instance") 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") else: raise TypeError("A single destination holds keys through an Identity instance") def encrypt(self, plaintext): if self.type == Destination.PLAIN: return plaintext if self.type == Destination.SINGLE and self.identity != None: return self.identity.encrypt(plaintext) 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.identity != None: return self.identity.decrypt(ciphertext) if self.type == Destination.GROUP: return self.prv.decrypt(base64.urlsafe_b64encode(ciphertext)) def sign(self, message): if self.type == Destination.SINGLE and self.identity != None: return self.identity.sign(message) else: return None # Creates an announce packet for this destination. # Application specific data can be added to the announce. def announce(self,app_data=None): pass