Create caeser_cipher.py

DSA/Cryptography/caeser_cipher.py

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+# import string module to use ascii_lowercase
+import string
+
+# define alphabet variable to use ascii_lowercase
+alphabet = string.ascii_lowercase
+
+# define encryption function
+def encrypt(text, shift):
+	# define empty string to store encrypted text
+	encrypted_text = ""
+	# loop through each character in text
+	for char in text:
+		# if character is not in alphabet, add to encrypted_text
+		if char not in alphabet:
+			encrypted_text += char
+		# else, add shifted character to encrypted_text
+		else:
+			encrypted_text += alphabet[(alphabet.index(char) + shift) % 26]
+	# return encrypted_text
+	return encrypted_text
+
+# define decryption function
+def decrypt(text, shift):
+	# define empty string to store decrypted text
+	decrypted_text = ""
+	# loop through each character in text
+	for char in text:
+		# if character is not in alphabet, add to decrypted_text
+		if char not in alphabet:
+			decrypted_text += char
+		# else, add shifted character to decrypted_text
+		else:
+			decrypted_text += alphabet[(alphabet.index(char) - shift) % 26]
+	# return decrypted_text
+	return decrypted_text
+
+# define main function
+def main():
+	# define text variable
+	plain_text = input("Enter Some Text: ")
+	# define shift variable
+	key = int(input("Enter Key: "))
+	# call encrypt function with text and shift variables
+	encrypted_text = encrypt(plain_text, key)
+	# print encrypted_text
+	print(encrypted_text)
+	# call decrypt function with encrypted_text and shift variables
+	decrypted_text = decrypt(encrypted_text, key)
+	# print decrypted_text
+	print(decrypted_text)
+
+# call main function
+main()