# -*- coding: utf-8 -*-
"""
Created on Sat Dec 2 14:54:19 2023
@author: ML
"""
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
initia_lpermutation_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]
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
# 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, initia_lpermutation_table)
 encrypted_blocks.append(encrypted_block)
 encrybted_message=hex(int(encrypted_block,2))
 
 
print("Encrypted Text:", encrybted_message)ضيف على هذا الكود فانكشن ال Final permutation