moth/puzzles/crypto/240diffie.py

26 lines
897 B
Python
Raw Normal View History

2009-10-15 12:34:58 -06:00
import crypto
import cbc
import diffie
import hashlib
IV = [0xaa]*64
aliceKey = hashlib.sha512(bytes('alice.%d' % diffie.key, 'utf-8')).digest()
bobKey = hashlib.sha512(bytes('bob.%d' % diffie.key, 'utf-8')).digest()
alice = b"""Only one more puzzle to go. They'll never get it though, since we use a one time pad. I need to add more text here to pad this."""
bob = b"""I wouldn't be so sure of that. The key is: in the same vein """
def C(text, key):
out = bytearray()
for i in range( len( text ) ):
out.append(key[i] ^ text[i])
return bytes(out)
c = cbc.cipherBlockChainingE(aliceKey, IV, C, alice)
print('<dl><dt>Alice<dd>', crypto.hexFormat(c))
assert cbc.cipherBlockChainingD(aliceKey, IV, C, c) == alice
c = cbc.cipherBlockChainingE(bobKey, IV, C, bob)
assert cbc.cipherBlockChainingD(bobKey, IV, C, c) == bob
print('<dt>Bob<dd>', crypto.hexFormat(c), '</dl>')