# zears

Implementation of [AEZ v5](https://www.cs.ucdavis.edu/~rogaway/aez/index.html) in Rust. Works without hardware AES support.

## ☣️ Cryptographic hazmat ☣️

This crate is not battle tested and not audited. It exists as a learning exercise. Use it at your own risk.

## AEZ encryption

From the AEZ website:

> AEZ is an authenticated-encryption (AE) scheme optimized for ease of correct use ("AE made EZ"). It was invented by Viet Tung Hoang, Ted Krovetz, and Phillip Rogaway. The algorithm encrypts a plaintext by appending to it a fixed authentication block (some zero bits) and then enciphering the resulting string with an arbitrary-input-length blockcipher, this tweaked by the nonce, AD, and authenticator length. The approach results in strong security and usability properties, including nonce-reuse misuse resistance, automatic exploitation of decryption-verified redundancy, and arbitrary, user-selectable length expansion.

## Example use

This crate provides an easy-to-use interface for AEZ:

```rust
use zears::Aez;
let aez = Aez::new(b"my key");
let ciphertext = aez.encrypt(b"nonce", &[b"associated data"], 16, b"message");
let plaintext = aez.decrypt(b"nonce", &["associated data"], 16, &ciphertext);
assert_eq!(plaintext.unwrap(), b"message");
```

## License

This crate is licensed under the terms of the MIT license. You can find the full license text in LICENSE.