rust_rsa

About this repo

This is my Rust implementation of the RSA encryption standard, based on this book.
This is for my CS 3000 - Advanced Algorithms & Data Structures class at SUU, taught by Professor Nathan Barker in the Spring 2022 semester.

How to use

Prerequisities

A Rust compiler that supports version 2021.
Having e.txt in the same working directory as the binary, once built. Should be a small-ish prime number, 65537 is a great starter.
Having message.txt in the same working directory as the binary, once built. Should be a message you wish to encode!

Building and Testing

Just run cargo test to ensure everything works as intended, and then run cargo build --release to get a binary.
Once you have this binary, a command line interface is exposed.

CLI

Running anything other than one of three preset commands will give you the help screen. Here it is now:

Help for RSA
List of possible args: [gen, encrypt, decrypt]
gen -> Generates and writes `d.txt` and `n.txt` to the current directory. Takes A WHILE even on good computers.
encrypt -> Takes `message.txt`, `e.txt`, and `n.txt` and encrypts the message, outputting `encryptedMessage.txt`.
decrypt -> Takes `encryptedMessage.txt`, `d.txt`, and `n.txt` and decrypts the message, printing it out in the console.

Using it to encrypt then decrypt a message

You basically just go in the order of CLI args.
First, you gen your public and private keys. Note that this took about 2 minutes on my decently-powered computer, as it has to keep randomly trying until it gets a prime.
Next, you have it encrypt your message.txt using encrypt and it spits out encryptedMessage.txt.
Finally, you run decrypt to decrypt encryptedMessage.txt and output it to your console!