def pad_plaintext(plaintext):
    while len(plaintext) < 8:
        plaintext += "@"
    return plaintext[:8]

    
def text_to_binary(text):
    binary_text = ""
    for char in text:
        binary_char = bin(ord(char))[2:].zfill(8)
        binary_text += binary_char
    return binary_text


def split_blocks(plaintext):
    blocks = []
    while len(plaintext) > 0:
        blocks.append(plaintext[:8])
        plaintext = plaintext[8:]
    return blocks


def ascii_to_binary_key(key):
    binary_key = ""
    for char in key:
        binary_key += format(ord(char), '08b')
    return binary_key


def apply_key_permutation(binary_key, permutation_table):
    permuted_key = ""
    for index in permutation_table:
        permuted_key += binary_key[index - 1]
    return permuted_key


def generate_subkeys(key):
    pc_1_table = [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]

    pc_2_table = [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]

    if len(key) != 8:
        raise ValueError("Key size must be 8 characters.")

    binary_key = ascii_to_binary_key(key)

    permuted_key = apply_key_permutation(binary_key, pc_1_table)

    # Convert key to numeric value
    permuted_key = int(permuted_key, 2)

    subkeys = []

    # Generate subkeys for each round
    for round in range(1, 17):
        # Left shifts for left half and right half of the key
        left_shifts = 1 if round in [1, 2, 9, 16] else 2
        permuted_key = ((permuted_key << left_shifts) & 0xFFFFFFFFFFFF) | (
            permuted_key >> (28 - left_shifts))

        # Use PC-2 table to convert the key to a 48-bit subkey
        subkey = apply_key_permutation(
            bin(permuted_key)[2:].zfill(56), pc_2_table)
        subkeys.append(subkey)

    return subkeys

initia_lpermutation_table= [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]
def initial_permutation(block):
    # Perform initial permutation on the block
    if len(block)<64:
        block = block.zfill(64)
    permuted_block = ""
    for index in initia_lpermutation_table:
        permuted_block += block[index - 1]
    return permuted_block

# Perform expansion permutation on the block
expansion_table = [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]
     
def expand_permutation(block):
    
    expanded_block=""
    for index in expansion_table:
        expanded_block += block[index - 1]
    return expanded_block


def substitute(s_box_input, s_box_index):
  s_boxes = [[[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]],
 
        [[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]],
 
        [[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]],
 
        [[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]],
 
        [[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]],
 
        [[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]],
 
        [[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]],
 
        [[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]]]

   
  
  row = int(s_box_input[0] + s_box_input[3], 2)
  column = int(s_box_input[1:3], 2)
  value = s_boxes[s_box_index][row][column]
  return bin(value)[2:].zfill(4)


def encrypt(plaintext, key):
    plaintext = pad_plaintext(plaintext)
    binary_text = text_to_binary(plaintext)
    blocks = split_blocks(binary_text)
    subkeys = generate_subkeys(key)

    encrypted_blocks = []

    for block in blocks:
        block = initial_permutation(block)
    if len(block)<32:
        block = block.zfill(32)
        left_half = block[:32]
        right_half = block[32:]

        for round in range(1, 17):
            previous_left_half = left_half

            # Expansion permutation
            right_expanded = expand_permutation(right_half)

            # XOR with round subkey
            subkey = subkeys[round - 1]
            right_expanded = bin(int(right_expanded, 2) ^
                                 int(subkey, 2))[2:].zfill(48)

            # S-box substitution
            s_box_input = ""
            for i in range(0, 48, 6):
                s_box_input += substitute(right_expanded[i:i+6], i//6)

            # Permutation
            permutation_table = [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]
            right_half = apply_key_permutation(s_box_input, permutation_table)

            # XOR with previous left half
            right_half = bin(int(right_half, 2) ^ int(
                previous_left_half, 2))[2:].zfill(32)

            # Swap left and right halves
            left_half, right_half = right_half, left_half

        # Final permutation
        encrypted_block = apply_key_permutation(
            right_half+left_half,initia_lpermutation_table)
        encrypted_blocks.append(encrypted_block)

    encrypted_text = ""
    for block in encrypted_blocks:
        for i in range(0, 8, 8):
            encrypted_text += chr(int(block[i:i+8], 2))

    return encrypted_text
Final_permutation_table=[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]

# Take user input for plaintext and key
plaintext = input("Enter the plaintext: ")
key = input("Enter the key (8 characters): ")

# Encrypt the plaintext using the key
encrypted_text = encrypt(plaintext, key)

# Print the encrypted text
binary_text = text_to_binary(plaintext)
blocks = split_blocks(binary_text)
subkeys = generate_subkeys(key)

encrypted_blocks = []

for block in blocks:
        block = initial_permutation(block)

        left_half = block[:32]
        right_half = block[32:]

        for round in range(1, 17):
            previous_left_half = left_half

            # Expansion permutation
            right_expanded = expand_permutation(right_half)

            # XOR with round subkey
            subkey = subkeys[round - 1]
            right_expanded = bin(int(right_expanded, 2) ^
                                 int(subkey, 2))[2:].zfill(48)

            # S-box substitution
            s_box_input = ""
            for i in range(0, 48, 6):
                s_box_input += substitute(right_expanded[i:i+6], i//6)

            # Permutation
            permutation_table = [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]
            right_half = apply_key_permutation(s_box_input, permutation_table)

            # XOR with previous left half
            right_half = bin(int(right_half, 2) ^ int(
                previous_left_half, 2))[2:].zfill(32)

            # Swap left and right halves
            left_half, right_half = right_half, left_half
           
        # Final permutation
        encrypted_block = apply_key_permutation(right_half + left_half,Final_permutation_table )
        encrypted_blocks.append(encrypted_block)
        #ascii_value=[ord(char)for char in encrypted_block]
        
print("Encrypted Text:",encrypted_block )اعمل فانكشن ال decryption تاخد ال encrypted_block وبتعكس ال key وبتطلع ال plaintext