def decryptAndValidate(IV, ct):
global GLOBAL_KEY
global BLOCK_SIZE
pt = AES_CBC.AES_CBCdecrypt(ct, GLOBAL_KEY, IV)
#print(pt[len(pt)-2:len(pt)])
isValidPadding = PKCS7.PKCS7validate(pt, BLOCK_SIZE)
return isValidPadding
def decryptAndCheckForAdmin(ctBytes):
pt = AES_CBC.AES_CBCdecrypt(ctBytes, GLOBAL_KEY, IV)
isValidPadding = PKCS7.PKCS7validate(pt, 16)
if isValidPadding:
pad = pt[len(pt) - 1]
pt = pt[:len(pt) - pad]
isAdminTuplePresent = checkForAdminTuple(pt.decode('latin1'))
#TODO: find how to change to pt.decode('utf-8')
return isAdminTuplePresent
else:
return None
def keyExchangeProtocol():
p_A, g_A = DiffieHellman.p, DiffieHellman.g
keyPairA = DiffieHellman.generateKeyPair(p_A, g_A)
A = keyPairA[1]
print("A to B: p, g, A")
keyPairB = DiffieHellman.generateKeyPair(p_A, g_A)
B = keyPairB[1]
print("B to A: B")
secretKeyA = DiffieHellman.DH(B, keyPairA, p_A)
secretKeyB = DiffieHellman.DH(A, keyPairB, p_A)
messageA = 'This is my message suckerr.\nYour\'s Sincerely\nA'
messageA = bytes(messageA.encode('latin1'))
secretKeyA_bytes = bytes.fromhex(hex(secretKeyA)[2:])
AESkeyA = hashlib.sha1(secretKeyA_bytes).digest()[:16]
IV_A = helpers.getRandBytes(16)
ct = AES_CBC.AES_CBCencrypt(PKCS7.PKCS7(messageA, 16), AESkeyA, IV_A)
secretKeyB_bytes = bytes.fromhex(hex(secretKeyB)[2:])
AESkeyB = hashlib.sha1(secretKeyB_bytes).digest()[:16]
pt = AES_CBC.AES_CBCdecrypt(ct, AESkeyB, IV_A)
if PKCS7.PKCS7validate(pt, 16):
pt = PKCS7.PKCS7unpad(pt)
else:
raise Exception('Something is wrong')
IV_B = helpers.getRandBytes(16)
ct_BtoA = AES_CBC.AES_CBCencrypt(PKCS7.PKCS7(pt, 16), AESkeyB, IV_B)
messageA2 = AES_CBC.AES_CBCdecrypt(ct_BtoA, AESkeyA, IV_B)
if PKCS7.PKCS7validate(messageA2, 16):
messageA2 = PKCS7.PKCS7unpad(messageA2)
else:
raise Exception('Something is wrong')
if messageA == messageA2:
print('Connection established')
else:
print('No connection')
def decrypt(ctBytes):
pt = AES_CBC.AES_CBCdecrypt(ctBytes, GLOBAL_KEY, GLOBAL_IV)
isValidPadding = PKCS7.PKCS7validate(pt, 16)
if isValidPadding:
pad = pt[len(pt) - 1]
pt = pt[:len(pt) - pad]
try:
pt.decode('utf-8')
except:
print('Error, high value ascii found')
return pt
else:
return None
else:
return None
def MITM():
p_A, g_A = DiffieHellman.p, DiffieHellman.g
keyPairA = DiffieHellman.generateKeyPair(p_A, g_A)
A = keyPairA[1]
print("A to B: p, g, A")
print("Intercepted by M")
keyPairB = DiffieHellman.generateKeyPair(p_A, g_A)
B = keyPairB[1]
print("M to B: p, g, p")
print("B to M: B")
print("M to A: p")
secretKeyA = DiffieHellman.DH(p_A, keyPairA, p_A)
secretKeyB = DiffieHellman.DH(p_A, keyPairB, p_A)
messageA = 'This is my message suckerr.\nYour\'s Sincerely\nA'
messageA = bytes(messageA.encode('latin1'))
secretKeyA_bytes = bytes.fromhex(
hex(secretKeyA)[2:] if len(hex(secretKeyA)[2:]) % 2 == 0 else '0' +
hex(secretKeyA)[2:])
AESkeyA = hashlib.sha1(secretKeyA_bytes).digest()[:16]
IV_A = helpers.getRandBytes(16)
ct = AES_CBC.AES_CBCencrypt(PKCS7.PKCS7(messageA, 16), AESkeyA, IV_A)
secretKeyB_bytes = bytes.fromhex(
hex(secretKeyB)[2:] if len(hex(secretKeyB)[2:]) % 2 == 0 else '0' +
hex(secretKeyB)[2:])
AESkeyB = hashlib.sha1(secretKeyB_bytes).digest()[:16]
pt = AES_CBC.AES_CBCdecrypt(ct, AESkeyB, IV_A)
if PKCS7.PKCS7validate(pt, 16):
pt = PKCS7.PKCS7unpad(pt)
else:
raise Exception('Something is wrong')
IV_B = helpers.getRandBytes(16)
ct_BtoA = AES_CBC.AES_CBCencrypt(PKCS7.PKCS7(pt, 16), AESkeyB, IV_B)
messageA2 = AES_CBC.AES_CBCdecrypt(ct_BtoA, AESkeyA, IV_B)
if PKCS7.PKCS7validate(messageA2, 16):
messageA2 = PKCS7.PKCS7unpad(messageA2)
else:
raise Exception('Something is wrong')
if messageA == messageA2:
print('Connection established')
else:
print('No connection')
AESkeyM = hashlib.sha1(bytes.fromhex('00')).digest()[:16]
messageA = 'Message 1'
messageA = bytes(messageA.encode('latin1'))
IV_A = helpers.getRandBytes(16)
ct = AES_CBC.AES_CBCencrypt(PKCS7.PKCS7(messageA, 16), AESkeyA, IV_A)
print('A:', messageA)
messageM = AES_CBC.AES_CBCdecrypt(ct, AESkeyM, IV_A)
if PKCS7.PKCS7validate(messageM, 16):
messageM = PKCS7.PKCS7unpad(messageM)
print('M:', messageM)
else:
raise Exception('Something is wrong')
messageB = AES_CBC.AES_CBCdecrypt(ct, AESkeyB, IV_A)
if PKCS7.PKCS7validate(messageB, 16):
messageB = PKCS7.PKCS7unpad(messageB)
print('B:', messageB)
else:
raise Exception('Something is wrong')