コード例 #1
0
ファイル: xortools.py プロジェクト: bmcd87/crypto
def breakxor(raw, keysize=-1):
    if(keysize == -1):
        distances = get_probable_key_sizes(raw)
    else:
        diff = get_normalized_distance(raw, keysize, 4)
        distances = [Distance(keysize, diff)]
    best_decrypted = None
    best_score = None
    for dist in distances:
        keysize = dist.keysize

        blocks = [[] for _ in range(keysize)]
        for i in range(0, len(raw)):
            pos = i % keysize
            blocks[pos].append(raw[i])

        key = bytearray()
        for block in blocks:
            b, output, score = solve_xor_block(block)
            key.append(b)
        
        decrypted = xor_repeating(raw, key)
        score = frequency.scoreof(decrypted)
        if( best_score is None or score < best_score):
            best_decrypted = (key, decrypted)
            best_score = score

    return best_decrypted
コード例 #2
0
ファイル: xortools.py プロジェクト: bmcd87/crypto
def solve_xor_block(encoded_bytes):
    current_score = 0
    current_byte = None
    current_bytes = None
    for b in range(0, 256):
        test_byte = bytes([b])[0]
        decoded_bytes = xor_against_byte(encoded_bytes, test_byte)
        score = frequency.scoreof(decoded_bytes)
        if current_score == 0 or score < current_score:
            current_score = score 
            current_byte = test_byte
            current_bytes = decoded_bytes
    return (current_byte, current_bytes, current_score)