This is a repo for implementing ciphers from throughout history in python.

It currently contains a shift cipher (aka Caesar's Cipher), and an alphabet substitution cipher.

To run this, launch the cipher.py and provide the following arguments:

-h, --help show this help message and exit
--key KEY secret word for substitution encryption
--action ACTION options: encrypt, decrypt
--cipher CIPHER options: shift, substitution
--N N Alphabet offset(rotation cipher only)
--text TEXT Message to encrypt or decrypt

For example here is an encrypt / decrypt using the substitution cipher:

python3 cipher.py --cipher substitution --action encrypt --key "Greenday" --text "Hello World"
Encrypted message: bdhhkzukohn

python3 cipher.py --cipher substitution --action decrypt --key "Greenday" --text "bdhhkzukohn"
Decrypted message: hello world

And the same with shift cipher:

python3 cipher.py --cipher shift --action encrypt --text "Hello World" --N 7
Encrytped message: olssv dvysk

python3 cipher.py --cipher shift --action decrypt --text "olssv dvysk" --N 7
Decrytped message: hello world