Spring Security 모듈의 StandardPasswordEncoder encode() 함수를 구현

sha256_encode.py

def sha256_encode(secret, password):
    """
    Spring Security 모듈의 StandardPasswordEncoder encode() 함수를 구현

    :param secret:
    :param password:
    :return:
    """
    salt_key_length = 8
    max_hash_rounds = 1024

    def gen_salt(n): return bytearray(map(random.getrandbits, (8,) * n))

    def concatenate(list_of_array):
        length = 0
        for arr in list_of_array:
            length += len(arr)

        new_array = bytearray(length)
        pos = 0
        for arr in list_of_array:
            new_array[pos:] = arr
            pos += len(arr)
        return new_array

    salt = gen_salt(salt_key_length)
    summed = concatenate([salt,
                          secret.encode('utf-8'),
                          password.encode('utf-8')])

    digested = summed
    for _ in range(max_hash_rounds):
        m = hashlib.sha256()
        m.update(digested)
        digested = m.digest()

    ret = concatenate([salt, digested])
    return binascii.hexlify(ret)