Curve25519 signatures like in the early Axolotl

Rust

Import

use ed25519_axolotl::{
    fast_signature,
    full_signature,
    decode_message,
    random_bytes,
    str_to_vec32,
    vec32_to_str,
    KeyPair
    verify,
};

Generate New KeyPair

// seed: Vec<u32>
// let keys = KeyPair::new(Some(seed));
let keys = KeyPair::new(None);

println!("{}", keys);

Fast Signature

• 64 byte signature
• quick to sign and verify
• don't possible to decode signature back to message

let keys = KeyPair::new(None);

let msg = str_to_vec32("hello e25519 axolotl".to_string());
let signature = fast_signature(
    keys.prvk,
    msg.clone(),
    Some(random_bytes(64))
);

assert_eq!(verify(keys.pubk, msg, signature), true);
println!("ok");

Full Signature

• (64 + message length) byte signature
• slow to sign and verify
• it is possible to decode the signature back to the message

let keys = KeyPair::new(None);

let msg = str_to_vec32("hello e25519 axolotl".to_string());
let signature = full_signature(
    keys.prvk,
    msg.clone(),
    Some(random_bytes(64))
);

assert_eq!(verify(keys.pubk, msg, signature), true);
println!("ok");

Decode Message

• possible only for full_signature function

let keys = KeyPair::new(None);

let msg = str_to_vec32("hello e25519 axolotl".to_string());
let mut sign_msg = full_signature(
    keys.prvk,
    msg.clone(),
    Some(random_bytes(64))
);
let decoded_msg = decode_message(keys.pubk, &mut sign_msg);

assert_eq!(msg, decoded_msg);
println!("ok");

NodeJs (WebAssembly)

Import

import * as wasm from "ed25519_axolotl";

or

const wasm = require("ed25519_axolotl")

Generate New KeyPair

const keys = new wasm.KeyPair()

console.log(keys.privateKey) // Uint32Array
console.log(keys.publiKey) // Uint32Array

Fast Signature

• 64 byte signature
• quick to sign and verify
• don't possible to decode signature back to message

const keys = new wasm.KeyPair()

console.log(keys.privateKey) // Uint32Array
console.log(keys.publiKey) // Uint32Array

const msg = wasm.stringToUint32Array("hello lunes")
console.log(msg) // Uint32Array

const signature = wasm.fastSignature(k.privateKey, msg, wasm.randomBytes(64))
console.log(signature) // Uint32Array

Full Signature

• (64 + message length) byte signature
• slow to sign and verify
• it is possible to decode the signature back to the message

const keys = new wasm.KeyPair()

console.log(keys.privateKey) // Uint32Array
console.log(keys.publiKey) // Uint32Array

const msg = wasm.stringToUint32Array("hello lunes")
console.log(msg) // Uint32Array

const signature = wasm.fullSignature(k.privateKey, msg, wasm.randomBytes(64))
console.log(signature) // Uint32Array

Decode Message

• possible only for full_signature function

const keys = new wasm.KeyPair()

console.log(keys.privateKey) // Uint32Array
console.log(keys.publiKey) // Uint32Array

const msg = wasm.stringToUint32Array("hello lunes")
console.log(msg) // Uint32Array

const signature = wasm.fullSignature(k.privateKey, msg, wasm.randomBytes(64))
console.log(signature) // Uint32Array

const dmsg = wasm.uint32ArrayToString(
    wasm.decode_message(k.publiKey, fl)
)
console.log(dmsg) // String

Python (C/C++)

Import

Generate New KeyPair

Fast Signature

• 64 byte signature
• quick to sign and verify
• don't possible to decode signature back to message

Full Signature

• (64 + message length) byte signature
• slow to sign and verify
• it is possible to decode the signature back to the message

Decode Message

• possible only for full_signature function

Credits

• Ported to Rust by Miguel Sandro Lucero, [email protected], 2021.09.11.

• You can use it under MIT or CC0 license.

• Curve25519 signatures idea and math by Trevor Perrin, see here

• Derived from axlsign.js written by Dmitry Chestnykh, see here