des.py

ip = [58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4,
      62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8,
      57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3,
      61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7]

ip_inv = [40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31,
          38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29,
          36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27,
          34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25]

expansion = [32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9,
             8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17,
             16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25,
             24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1]

permutation_box = [16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10,
                   2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25]


def d(lis):
    """
    show list in string
    :param lis:
    :return: string
    """
    return "".join(str(x) for x in lis)


def rotate_left(data, n):
    """
    left shift 
    :param data:
    :param n:
    :return: array of data
    """
    return data[n:] + data[:n]


def str2bin(msg):
    """
    string to binary
    :param msg: 
    :return: array of binary
    """
    dummy = []
    for i in range(len(msg)):
        bits = bin(ord(msg[i]))[2:]
        bits = '00000000'[len(bits):] + bits
        dummy.extend([int(b) for b in bits])
    return dummy


def key_builder(ext_key):
    """
    build internal key from external key
    :param ext_key: 
    :return: key 
    """
    pc1 = [57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18,
           10, 2, 59, 51, 43, 35, 27, 19, 11, 3, 60, 52, 44, 36,
           63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22,
           14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20, 12, 4]

    pc2 = [14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10,
           23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2,
           41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
           44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32]

    key_round = [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1]

    raw_result = []
    final_key = []

    for i in range(len(pc1)):
        raw_result.append(ext_key[pc1[i] - 1])

    left = raw_result[:28]
    right = raw_result[28:]

    for i in range(len(key_round)):
        left = rotate_left(left, key_round[i])
        right = rotate_left(right, key_round[i])
        ki = left + right
        aur = []
        for j in range(len(pc2)):
            aur.append(ki[pc2[j] - 1])
        final_key.append(aur)

    return final_key


def split_message(msg):
    """
    split message to list, each index have 64-bit data
    :param msg:
    :return: msg_split
    """
    msg_split = []

    j = 0
    for i in range(0, len(msg), 64):
        msg_split.append(msg[i:i + 64])

        if len(msg_split[j]) < 64:
            miss = 64 - len(msg_split[j])
            padding = "".join(str(int(x * 0)) for x in range(miss))
            msg_split[j].extend([int(b) for b in padding])
        j += 1

    return msg_split


def permutation_function(msg, table):
    """
    permutation array of message by table
    :param msg: 
    :param table: 
    :return: array
    """
    dummy = []
    for i in range(len(table)):
        dummy.append(msg[table[i] - 1])

    return dummy


def xor_with_key(msg, key_f):
    """
    xor message with key
    :param msg: 
    :param key_f: 
    :return: array
    """
    dummy = []
    for i in range(len(msg)):
        dummy.append(msg[i] ^ key_f[i])

    return dummy


def s_box(msg):
    """
    permutation data with s-box
    :param msg: 
    :return: array
    """
    s1 = [[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, ],
          [0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, ],
          [4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, ],
          [15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13, ], ]

    s2 = [[15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, ],
          [3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, ],
          [0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, ],
          [13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9, ], ]

    s3 = [[10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, ],
          [13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, ],
          [13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, ],
          [1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12, ], ]

    s4 = [[7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, ],
          [13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, ],
          [10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, ],
          [3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14, ], ]

    s5 = [[2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, ],
          [14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, ],
          [4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, ],
          [11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3, ], ]

    s6 = [[12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, ],
          [10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, ],
          [9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, ],
          [4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13, ], ]

    s7 = [[4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, ],
          [13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, ],
          [1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, ],
          [6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12, ], ]

    s8 = [[13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, ],
          [1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, ],
          [7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, ],
          [2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11, ], ]

    s = [s1, s2, s3, s4, s5, s6, s7, s8]

    b = []
    index = 0
    for k in range(8):
        ar = msg[index:index + 6]
        index += 6
        row = int(str(ar[0]) + str(ar[5]), 2)
        column = int(''.join([str(x) for x in ar[1:5]]), 2)
        value = bin(s[k][row][column])[2:]
        value = '0000'[len(value):] + value
        b.extend([int(x) for x in value])

    return b


def encrypt(messages, internal_key):
    """
    encrypt message with key
    :param messages: 
    :param internal_key: 
    :return: ciphertext
    """
    messages = split_message(messages)
    cipher = ""

    for msg in messages:
        permutation = permutation_function(msg, ip)
        left, right = permutation[:32], permutation[32:]

        for i in range(16):
            expand = permutation_function(right, expansion)
            vector_a = xor_with_key(expand, internal_key[i])
            vector_b = s_box(vector_a)
            pb = permutation_function(vector_b, permutation_box)
            temp = right
            right = []
            for k in range(len(pb)):
                right.append(pb[k] ^ left[k])
            left = temp

        raw = right + left
        final = permutation_function(raw, ip_inv)
        cipher += "".join(str(x) for x in final)

    return cipher


def decrypt(messages, internal_key):
    """
    decrypt ciphertext by key
    :param messages: 
    :param internal_key: 
    :return: plaintext
    """
    messages = split_message(messages)
    plaintext = ""

    for msg in messages:
        permutation = permutation_function(msg, ip)
        left, right = permutation[:32], permutation[32:]

        for i in range(15, -1, -1):
            expand = permutation_function(right, expansion)
            vector_a = xor_with_key(expand, internal_key[i])
            vector_b = s_box(vector_a)
            pb = permutation_function(vector_b, permutation_box)
            temp = right
            right = []
            for k in range(len(pb)):
                right.append(pb[k] ^ left[k])
            left = temp

        raw = right + left
        final = permutation_function(raw, ip_inv)
        plaintext += "".join(str(x) for x in final)

    return plaintext


# open key
externalKey = open('pass.txt', 'r').read()
key_in_binary = str2bin(externalKey)
key = key_builder(key_in_binary)

# message 8-byte (text)
# message = open('message.txt', 'r').read()
# message = str2bin(message)

# message in json (more than 8-byte)
message = open('example.json', 'r').read()
message = str2bin(message)

# encrypt message
ciphertext = encrypt(message, key)
print("Ciphertext =", ciphertext)

aa = []
aa.extend([int(x) for x in ciphertext])

# decrypt message
print("Plaintext =", d(message))
print("Plaintext =", decrypt(aa, key))