Reticulum/RNS/Identity.py

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import base64
import math
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import os
import RNS
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import time
import atexit
import cPickle
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from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
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from cryptography.hazmat.primitives.serialization import load_der_public_key
from cryptography.hazmat.primitives.serialization import load_der_private_key
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from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives.asymmetric import padding
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class Identity:
# Configure key size
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KEYSIZE = 1536
DERKEYSIZE = 1808
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# Padding size, not configurable
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PADDINGSIZE= 336
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# Storage
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known_destinations = {}
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def __init__(self,public_only=False):
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# Initialize keys to none
self.prv = None
self.pub = None
self.prv_bytes = None
self.pub_bytes = None
self.hash = None
self.hexhash = None
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if not public_only:
self.createKeys()
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@staticmethod
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def remember(packet_hash, destination_hash, public_key, app_data = None):
RNS.log("Remembering "+RNS.prettyhexrep(destination_hash), RNS.LOG_VERBOSE)
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Identity.known_destinations[destination_hash] = [time.time(), packet_hash, public_key, app_data]
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@staticmethod
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def recall(destination_hash):
RNS.log("Searching for "+RNS.prettyhexrep(destination_hash)+"...", RNS.LOG_DEBUG)
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if destination_hash in Identity.known_destinations:
identity_data = Identity.known_destinations[destination_hash]
identity = Identity(public_only=True)
identity.loadPublicKey(identity_data[2])
RNS.log("Found "+RNS.prettyhexrep(destination_hash)+" in known destinations", RNS.LOG_DEBUG)
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return identity
else:
RNS.log("Could not find "+RNS.prettyhexrep(destination_hash)+" in known destinations", RNS.LOG_DEBUG)
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return None
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@staticmethod
def saveKnownDestinations():
RNS.log("Saving known destinations to storage...", RNS.LOG_VERBOSE)
file = open(RNS.Reticulum.storagepath+"/known_destinations","w")
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cPickle.dump(Identity.known_destinations, file)
file.close()
RNS.log("Done saving known destinations to storage", RNS.LOG_VERBOSE)
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@staticmethod
def loadKnownDestinations():
if os.path.isfile(RNS.Reticulum.storagepath+"/known_destinations"):
file = open(RNS.Reticulum.storagepath+"/known_destinations","r")
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Identity.known_destinations = cPickle.load(file)
file.close()
RNS.log("Loaded "+str(len(Identity.known_destinations))+" known destinations from storage", RNS.LOG_VERBOSE)
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else:
RNS.log("Destinations file does not exist, so no known destinations loaded", RNS.LOG_VERBOSE)
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@staticmethod
def fullHash(data):
digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
digest.update(data)
return digest.finalize()
@staticmethod
def truncatedHash(data):
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digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
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digest.update(data)
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return digest.finalize()[:10]
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@staticmethod
def validateAnnounce(packet):
if packet.packet_type == RNS.Packet.ANNOUNCE:
RNS.log("Validating announce from "+RNS.prettyhexrep(packet.destination_hash), RNS.LOG_VERBOSE)
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destination_hash = packet.destination_hash
public_key = packet.data[10:Identity.DERKEYSIZE/8+10]
random_hash = packet.data[Identity.DERKEYSIZE/8+10:Identity.DERKEYSIZE/8+20]
signature = packet.data[Identity.DERKEYSIZE/8+20:Identity.DERKEYSIZE/8+20+Identity.KEYSIZE/8]
app_data = ""
if len(packet.data) > Identity.DERKEYSIZE/8+20+Identity.KEYSIZE/8:
app_data = packet.data[Identity.DERKEYSIZE/8+20+Identity.KEYSIZE/8:]
signed_data = destination_hash+public_key+random_hash+app_data
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announced_identity = Identity(public_only=True)
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announced_identity.loadPublicKey(public_key)
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if announced_identity.pub != None and announced_identity.validate(signature, signed_data):
RNS.log("Announce is valid", RNS.LOG_VERBOSE)
RNS.Identity.remember(RNS.Identity.fullHash(packet.raw), destination_hash, public_key)
RNS.log("Stored valid announce from "+RNS.prettyhexrep(destination_hash), RNS.LOG_INFO)
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del announced_identity
return True
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else:
RNS.log("Announce is invalid", RNS.LOG_VERBOSE)
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del announced_identity
return False
@staticmethod
def exitHandler():
Identity.saveKnownDestinations()
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def createKeys(self):
self.prv = rsa.generate_private_key(
public_exponent=65337,
key_size=Identity.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
)
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self.updateHashes()
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RNS.log("Identity keys created for "+RNS.prettyhexrep(self.hash), RNS.LOG_INFO)
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def getPrivateKey(self):
return self.prv_bytes
def getPublicKey(self):
return self.pub_bytes
def loadPrivateKey(self, key):
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
)
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self.updateHashes()
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def loadPublicKey(self, key):
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try:
self.pub_bytes = key
self.pub = load_der_public_key(self.pub_bytes, backend=default_backend())
self.updateHashes()
except Exception as e:
RNS.log("Error while loading public key, the contained exception was: "+str(e), RNS.LOG_ERROR)
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def updateHashes(self):
self.hash = Identity.truncatedHash(self.pub_bytes)
self.hexhash = self.hash.encode("hex_codec")
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def saveIdentity(self):
pass
def loadIdentity(self):
pass
def encrypt(self, plaintext):
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if self.pub != None:
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chunksize = (Identity.KEYSIZE-Identity.PADDINGSIZE)/8
chunks = int(math.ceil(len(plaintext)/(float(chunksize))))
ciphertext = "";
for chunk in range(chunks):
start = chunk*chunksize
end = (chunk+1)*chunksize
if (chunk+1)*chunksize > len(plaintext):
end = len(plaintext)
ciphertext += self.pub.encrypt(
plaintext[start:end],
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA1()),
algorithm=hashes.SHA1(),
label=None
)
)
return ciphertext
else:
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raise KeyError("Encryption failed because identity does not hold a public key")
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def decrypt(self, ciphertext):
if self.prv != None:
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plaintext = None
try:
chunksize = (Identity.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)
plaintext += self.prv.decrypt(
ciphertext[start:end],
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA1()),
algorithm=hashes.SHA1(),
label=None
)
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)
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except:
RNS.log("Decryption by "+RNS.prettyhexrep(self.hash)+" failed")
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return plaintext;
else:
raise KeyError("Decryption failed because identity does not hold a private key")
def sign(self, message):
if 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:
raise KeyError("Signing failed because identity does not hold a private key")
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def validate(self, signature, message):
if self.pub != None:
try:
self.pub.verify(
signature,
message,
padding.PSS(
mgf=padding.MGF1(hashes.SHA256()),
salt_length=padding.PSS.MAX_LENGTH
),
hashes.SHA256()
)
return True
except:
return False
else:
raise KeyError("Signature validation failed because identity does not hold a public key")
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def prove(self, packet, destination):
proof_data = packet.packet_hash + self.sign(packet.packet_hash)
proof = RNS.Packet(destination, proof_data, RNS.Packet.PROOF)
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proof.send()
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def getRandomHash(self):
return self.truncatedHash(os.urandom(10))
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