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