Reticulum/RNS/Destination.py

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import base64
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import math
import RNS
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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
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class Callbacks:
def __init__(self):
self.link_established = None
self.packet = None
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self.proof_requested = None
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class Destination:
KEYSIZE = RNS.Identity.KEYSIZE;
PADDINGSIZE= RNS.Identity.PADDINGSIZE;
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# Constants
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SINGLE = 0x00
GROUP = 0x01
PLAIN = 0x02
LINK = 0x03
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types = [SINGLE, GROUP, PLAIN, LINK]
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PROVE_NONE = 0x21
PROVE_APP = 0x22
PROVE_ALL = 0x23
proof_strategies = [PROVE_NONE, PROVE_APP, PROVE_ALL]
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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]
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def __init__(self, identity, direction, type, app_name, *aspects):
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# 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")
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self.callbacks = Callbacks()
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self.type = type
self.direction = direction
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self.proof_strategy = Destination.PROVE_NONE
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self.mtu = 0
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self.links = []
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if identity != None and type == Destination.SINGLE:
aspects = aspects+(identity.hexhash,)
if identity == None and direction == Destination.IN:
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identity = Identity()
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aspects = aspects+(identity.hexhash,)
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self.identity = identity
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self.name = Destination.getDestinationName(app_name, *aspects)
self.hash = Destination.getDestinationHash(app_name, *aspects)
self.hexhash = self.hash.encode("hex_codec")
self.callback = None
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self.proofcallback = None
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RNS.Transport.registerDestination(self)
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def __str__(self):
return "<"+self.name+"/"+self.hexhash+">"
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def link_established_callback(self, callback):
self.callbacks.link_established = callback
def packet_callback(self, callback):
self.callbacks.packet = callback
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def proof_requested_callback(self, callback):
self.callbacks.proof_requested = callback
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def set_proof_strategy(self, proof_strategy):
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if not proof_strategy in Destination.proof_strategies:
raise TypeError("Unsupported proof strategy")
else:
self.proof_strategy = proof_strategy
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def receive(self, packet):
plaintext = self.decrypt(packet.data)
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if plaintext != None:
if packet.packet_type == RNS.Packet.LINKREQUEST:
self.incomingLinkRequest(plaintext, packet)
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if packet.packet_type == RNS.Packet.DATA:
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if self.callbacks.packet != None:
self.callbacks.packet(plaintext, packet)
def incomingLinkRequest(self, data, packet):
link = RNS.Link.validateRequest(self, data, packet)
if link != None:
self.links.append(link)
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def createKeys(self):
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if self.type == Destination.PLAIN:
raise TypeError("A plain destination does not hold any keys")
if self.type == Destination.SINGLE:
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raise TypeError("A single destination holds keys through an Identity instance")
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if self.type == Destination.GROUP:
self.prv_bytes = Fernet.generate_key()
self.prv = Fernet(self.prv_bytes)
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def getPrivateKey(self):
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if self.type == Destination.PLAIN:
raise TypeError("A plain destination does not hold any keys")
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elif self.type == Destination.SINGLE:
raise TypeError("A single destination holds keys through an Identity instance")
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else:
return self.prv_bytes
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def loadPrivateKey(self, key):
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if self.type == Destination.PLAIN:
raise TypeError("A plain destination does not hold any keys")
if self.type == Destination.SINGLE:
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raise TypeError("A single destination holds keys through an Identity instance")
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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")
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else:
raise TypeError("A single destination holds keys through an Identity instance")
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def encrypt(self, plaintext):
if self.type == Destination.PLAIN:
return plaintext
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if self.type == Destination.SINGLE and self.identity != None:
return self.identity.encrypt(plaintext)
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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:
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return ciphertext
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if self.type == Destination.SINGLE and self.identity != None:
return self.identity.decrypt(ciphertext)
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if self.type == Destination.GROUP:
return self.prv.decrypt(base64.urlsafe_b64encode(ciphertext))
def sign(self, message):
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if self.type == Destination.SINGLE and self.identity != None:
return self.identity.sign(message)
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else:
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return None
# Creates an announce packet for this destination.
# Application specific data can be added to the announce.
def announce(self,app_data=None):
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destination_hash = self.hash
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random_hash = RNS.Identity.getRandomHash()
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signed_data = self.hash+self.identity.getPublicKey()+random_hash
if app_data != None:
signed_data += app_data
signature = self.identity.sign(signed_data)
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# TODO: Check if this could be optimised by only
# carrying the hash in the destination field, not
# also redundantly inside the signed blob as here
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announce_data = self.hash+self.identity.getPublicKey()+random_hash+signature
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if app_data != None:
announce_data += app_data
RNS.Packet(self, announce_data, RNS.Packet.ANNOUNCE).send()
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