154 lines
4.5 KiB
Python
154 lines
4.5 KiB
Python
import base64
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import math
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import FPE
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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 Identity:
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# Configure key size
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KEYSIZE = 1536;
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# Padding size, not configurable
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PADDINGSIZE= 336;
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def __init__(self):
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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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self.hash = None
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self.hexhash = None
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self.createKeys()
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@staticmethod
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def getHash(pub_key):
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digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
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digest.update(pub_key)
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return digest.finalize()[:10]
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def createKeys(self):
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self.prv = rsa.generate_private_key(
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public_exponent=65337,
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key_size=Identity.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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self.hash = Identity.getHash(self.pub_bytes)
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self.hexhash = self.hash.encode("hex_codec")
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FPE.log("Identity keys created, private length is "+str(len(self.prv_bytes))+" public length is "+str(len(self.pub_bytes)), FPE.LOG_INFO)
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def getPrivateKey(self):
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return self.prv_bytes
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def getPublicKey(self):
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return self.pub_bytes
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def loadPrivateKey(self, key):
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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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def loadPublicKey(self, 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 saveIdentity(self):
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pass
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def loadIdentity(self):
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pass
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def encrypt(self, plaintext):
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if self.prv != None:
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chunksize = (Identity.KEYSIZE-Identity.PADDINGSIZE)/8
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chunks = int(math.ceil(len(plaintext)/(float(chunksize))))
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# TODO: Remove debug output 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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# TODO: Remove debug output 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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# TODO: Remove debug output print("Plaintext encrypted, ciphertext length is "+str(len(ciphertext))+" bytes.")
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return ciphertext
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else:
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raise KeyError("Encryption failed because identity does not hold a private key")
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def decrypt(self, ciphertext):
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if self.prv != None:
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# TODO: Remove debug output print("Ciphertext length is "+str(len(ciphertext))+". ")
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chunksize = (Identity.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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# TODO: Remove debug output 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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else:
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raise KeyError("Decryption failed because identity does not hold a private key")
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def sign(self, message):
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if 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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raise KeyError("Signing failed because identity does not hold a private key")
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def announce(self):
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pass |