Implementation of Caesar Cipher

caesar_cipher.py

# implementation of caesar cipher

# key - number of rotational positions
def encrypt(text, key):
	text_list = list(text)
	text_encrypt = ""
	for i in text_list:
		# check if char is a letter
		if (i >= 'a' and i <= 'z') or (i >= 'A' and i <= 'Z'):
			if (i >= 'a' and i <= 'z'):
				ord_c = (ord(i) - ord('a') + key) % 26
				text_encrypt += chr(ord_c + ord('a'))
			else:
				ord_c = (ord(i) - ord('A') + key) % 26
				text_encrypt += chr(ord_c + ord('A'))
		else:
			text_encrypt += i
	return text_encrypt

def decrypt(text, key):
	text_list = list(text)
	text_encrypt = ""
	for i in text_list:
		if (i >= 'a' and i <= 'z') or (i >= 'A' and i <= 'Z'):
			if (i >= 'a' and i <= 'z'):
				ord_c = (ord(i) - ord('a') - key) % 26
				text_encrypt += chr(ord_c + ord('a'))
			else:
				ord_c = (ord(i) - ord('A') - key) % 26
				text_encrypt += chr(ord_c + ord('A'))
		else:
			text_encrypt += i
	return text_encrypt

# test to entry: ABCDEFGHIJKLMNOPQRSTUVWXYZ
# shift (key): 23
# output: XYZABCDEFGHIJKLMNOPQRSTUVW
print(encrypt("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 23))
print(decrypt("XYZABCDEFGHIJKLMNOPQRSTUVW", 23))