def apply_table(inp, table):

return res

def left_shift(data):

return data[1:] + data[0]

def XOR(a, b):

return res

def apply_sbox(s, data):

row = int("0b" + data[0] + data[-1], 2)

col = int("0b" + data[1:3], 2)

return bin(s[row][col])[2:]

def function(expansion, s0, s1, key, message):

return temp + right

if __name__ == "__main__":

key = input("Enter 10 bit key: ")

message = input("Enter 8 bit message: ")

p8_table = [6, 3, 7, 4, 8, 5, 10, 9]

p10_table = [3, 5, 2, 7, 4, 10, 1, 9, 8, 6]

p4_table = [2, 4, 3, 1]

IP = [2, 6, 3, 1, 4, 8, 5, 7]

IP_inv = [4, 1, 3, 5, 7, 2, 8, 6]

expansion = [4, 1, 2, 3, 2, 3, 4, 1]

s0 = [[1, 0, 3, 2], [3, 2, 1, 0], [0, 2, 1, 3], [3, 1, 3, 2]]

s1 = [[0, 1, 2, 3], [2, 0, 1, 3], [3, 0, 1, 0], [2, 1, 0, 3]]

# key generation

temp = apply_table(key, p10_table)

left = temp[:5]

right = temp[5:]

left = left_shift(left)

right = left_shift(right)

key1 = apply_table(left + right, p8_table)

left = left_shift(left)

right = left_shift(right)

left = left_shift(left)

right = left_shift(right)

key2 = apply_table(left + right, p8_table)

# encryption

temp = apply_table(message, IP)

temp = function(expansion, s0, s1, key1, temp)

temp = temp[4:] + temp[:4]

temp = function(expansion, s0, s1, key2, temp)

CT = apply_table(temp, IP_inv)

print("Cipher text is:", CT)

# decryption

temp = apply_table(CT, IP)

temp = function(expansion, s0, s1, key2, temp)

temp = temp[4:] + temp[:4]

temp = function(expansion, s0, s1, key1, temp)

PT = apply_table(temp, IP_inv)

print("Plain text after decypting is:", PT)