branca

Crate	Documentation	License	Travis

Branca is a secure alternative token format to JWT. This implementation is written in pure Rust and uses the XChaCha20-Poly1305 AEAD (Authenticated Encryption with Associated Data) stream cipher for generating authenticated and encrypted tamper-proof tokens. More information about the branca token specification can be found here in branca-spec.

Requirements

• Rust 1.18+
• Cargo

Installation

Add this line to your Cargo.toml under the dependencies section:

[dependencies]
branca = "^0.5.0"

Then you can import the crate into your project with these lines:

extern crate branca;
use branca::{Branca, encode, decode};

Example Usage

Encoding

let key = b"supersecretkeyyoushouldnotcommit".to_vec();
let nonce = *b"\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c";

let message = "Hello world!";
let timestamp = 123206400;
let branca_token = encode(message,key,nonce,timestamp).unwrap();

// branca_token = 875GH233T7IYrxtgXxlQBYiFobZMQdHAT51vChKsAIYCFxZtL1evV54vYqLyZtQ0ekPHt8kJHQp0a

Decoding

let ciphertext = branca_token.as_str();
let key = b"supersecretkeyyoushouldnotcommit".to_vec();
let ttl = 0; // The ttl can be used to determine if the supplied token has expired or not.
let decoded = decode(ciphertext, key, ttl);

if decoded.is_err() {
    // Error
} else {
    let msg = decoded.unwrap(); 
    // msg = "Hello world!"
}

Encode/Decode arbitrary data structures with Serde.

Since Branca is able to work with any format of data in the payload, it is possible for the payload to be anything from a JSON object, plaintext, raw bytes, protocol buffers or even a JWT.

Here is a example of using Branca to encode/decode a typical JSON object with serde_json.

Add the following into your Cargo.toml file:

[dependencies]
branca = "^0.5.0"
serde_json = "^1.0"
serde_derive = "1.0.83"
ring = "0.13.5"

#[macro_use]
extern crate serde_json;
#[macro_use]
extern crate serde_derive;
extern crate branca;
extern crate ring;

use branca::{encode, decode};
use ring::rand::{SystemRandom, SecureRandom};

#[derive(Serialize, Deserialize, Debug)]
struct User {
    user: String,
    scope: Vec<String>,
}

fn main(){

    let message = json!({
        "user" : "someone@example.com",
        "scope":["read", "write", "delete"],
    }).to_string();

    // Generate Nonce (24 bytes in length)
    let rand_nonce = SystemRandom::new();
    let mut nonce = vec![0; 24];
    rand_nonce.fill(nonce.as_mut()).unwrap();

    // Encode Message
    let key = b"supersecretkeyyoushouldnotcommit";
    let timestamp = 123206400;
    let branca_token = encode(message.as_str(), key.to_vec(), nonce, timestamp).unwrap();

    // Decode Message
    let payload = decode(branca_token.as_str(), key.to_vec(), 0).unwrap();
    let json: User = serde_json::from_str(payload.as_str()).unwrap();

    println!("{}", branca_token);
    println!("{}", payload);
    println!("{:?}", json);
}

You can use either Ring's SecureRandom or sodiumoxide's aead gen_nonce() or gen_key() for generating secure nonces and keys for example.

But do note that the nonce must be 24 bytes in length. Keys must be 32 bytes in length.

Building

cargo build

Testing

cargo test --examples

Contributing

Contributions and patches are welcome! Fork this repository, add your changes and send a PR.

Before you send a PR, make sure you run cargo test --examples first to check if your changes pass the tests.

If you would like to fix a bug or add a enhancement, please do so in the issues section and provide a short description about your changes.

License

MIT