Rail Fence Algorithm (E&D).py

def encrypt(s,n):
	fence = [[] for i in range(n)]
	rail = 0
	var = 1

	for char in s:
		fence[rail].append(char)
		rail += var

		if rail == n-1 or rail == 0:
			var = -var

	res = ''
	for i in fence:
		for j in i:
			res += j
	
	return res

def decrypt(s,n):
	fence = [[] for i in range(n)]
	rail  = 0
	var   = 1

	for char in s:
		fence[rail].append(char)
		rail += var

		if rail == n-1 or rail == 0:
			var = -var

	rFence = [[] for i in range(n)]

	i = 0
	l = len(s)
	s = list(s)
	for r in fence:
		for j in range(len(r)):
			rFence[i].append(s[0])
			s.remove(s[0])
		i += 1

	rail = 0
	var  = 1
	r = ''
	for i in range(l):
		r += rFence[rail][0]
		rFence[rail].remove(rFence[rail][0])
		rail += var

		if rail == n-1 or rail == 0:
			var = -var

	return r


plaintext=input("Enter PlainText: ")
depth = int(input("Enter Depth: "))

cyphertext = encrypt(plaintext, depth)
print("\nCipherText: ",cyphertext)

plaintext_rt = decrypt(cyphertext, depth)
print("\nPlainText: ",plaintext_rt)