Row_Column_Cipher.py

import math

key = "cipher"  #key = int(input("Enter the key value:"))

def encryptMessage(msg):
	cipher = ""
	k_indx = 0

	msg_len = float(len(msg))
	msg_lst = list(msg)
	key_lst = sorted(list(key))

	col = len(key)
	row = int(math.ceil(msg_len / col))

	fill_null = int((row * col) - msg_len)
	msg_lst.extend('_' * fill_null)

	matrix = [msg_lst[i: i + col]
			for i in range(0, len(msg_lst), col)]

	for _ in range(col):
		curr_idx = key.index(key_lst[k_indx])
		cipher += ''.join([row[curr_idx]
						for row in matrix])
		k_indx += 1
	return cipher

def decryptMessage(cipher):
	msg = ""
	k_indx = 0

	msg_indx = 0
	msg_len = float(len(cipher))
	msg_lst = list(cipher)
	col = len(key)

  row = int(math.ceil(msg_len / col))
	key_lst = sorted(list(key))

	dec_cipher = []
	for _ in range(row):
		dec_cipher += [[None] * col]

	for _ in range(col):
		curr_idx = key.index(key_lst[k_indx])

		for j in range(row):
			dec_cipher[j][curr_idx] = msg_lst[msg_indx]
			msg_indx += 1
		k_indx += 1

	try:
		msg = ''.join(sum(dec_cipher, []))
	except TypeError:
		raise TypeError("This program cannot",
						"handle repeating words.")

	null_count = msg.count('_')

	if null_count > 0:
		return msg[: -null_count]
	return msg

msg = input("enter the message: ")
cipher = encryptMessage(msg)
print("Encrypted Message: {}".
			format(cipher))

print("Decryped Message: {}".
	format(decryptMessage(cipher)))