full_recurse.py

def recurse(plaintexts, ciphertexts, kcands, keyers=[], depth=1):
    if depth > 5:
        return None, None
    for k in kcands:
        dciphertexts = ciphertexts[:]
        # DECRPYT CIPHERTEXTS WITH THE CURRENT KEY
        for pair in range(len(dciphertexts)):
            ci1, ci2 = map(int, dciphertexts[pair], repeat(16))
            # undo modular multiplication by odd-ed key, reversal,
            # xor by guessed key
            ci1 = g((ci1 * pow(k | 1, -1, 1 << 64)) % (1 << 64)) ^ k
            ci2 = g((ci2 * pow(k | 1, -1, 1 << 64)) % (1 << 64)) ^ k
            dciphertexts[pair] = [hex(ci1)[2:], hex(ci2)[2:]]
        # If the decrypted ciphertexts are the same as the plaintext, we're done!
        if all([int(dciphertexts[i][j], 16) == int(plaintexts[i][j], 2)
                for j in range(0, 2) for i in range(len(dciphertexts))]) == True:
            return dciphertexts, [k] + keyers

        # SOLVE FOR THE NEXT ODD-ED KEY
        dkcands = crack_subkey(dciphertexts)
        if dkcands is None:
            continue

        v = recurse(plaintexts, dciphertexts,
                    dkcands, [k] + keyers, depth + 1)
        if v is not None:
            return v