KYBER

A rust implementation of the post-quantum key exchange algorithm Kyber, packaged as a wasm binary.

This version currently uses kyber764, equivalent to a 192 bit security level. To use different variants or enable 90's mode, check the github instructions for how to compile it yourself.

Installation

npm -i pqc-kyber

Usage

import * as kyber from "pqc_kyber";

// Generate Keypair
let keys = kyber.keypair();
const publicKeyAlice = keys.pubkey;
const privateKeyAlice = keys.secret;

// Encapsulate secret
try {
    let encapsulated = kyber.encapsulate(publicKeyAlice);
    var ciphertextBob = encapsulated.ciphertext;
    var sharedSecretBob = encapsulated.sharedSecret;
}
catch(err) {
    alert("Error Encapsulating");
}

// Decapsulate secret
try {
    let decapsulated = kyber.decapsulate(ciphertextBob, privateKeyAlice);
    var sharedSecretAlice = decapsulated.sharedSecret
}
catch(err) {
    alert("Error Decapsulating");
}

var assert = require('assert');

assert.equal(sharedSecretAlice, sharedSecretBob)

// Valid input lengths are found in the `Params` class
assert.equal(publicKeyAlice.len(), kyber.Params.publicKeyBytes);
assert.equal(secretKeyAlice.len(), kyber.Params.secretKeyBytes);
assert.equal(ciphertextBob.len(),  kyber.Params.ciphertextBytes);
assert.equal(sharedSecretAlice.len(), kyber.Params.sharedSecretBytes)

Errors

Will be raised if:

• The ciphertext cannot be decapsulated with the private key
• Functions are given incorrectly sized byte arrays

Valid input sizes are all contained in the kyber.Params class.

Security Considerations

Kyber is relatively new, it is highly advised to use it in a hybrid key exchange system, alongside a traditional algorithm like X25519 rather than by itself.

For further reading the IETF have a draft construction for hybrid key exchange in TLS 1.3:

https://www.ietf.org/archive/id/draft-ietf-tls-hybrid-design-04.html

About

Kyber is an IND-CCA2-secure key encapsulation mechanism (KEM), whose security is based on the hardness of solving the learning-with-errors (LWE) problem over module lattices. It is the final standardised algorithm resulting from the NIST post-quantum cryptography project.

The official website: https://pq-crystals.org/kyber/

Authors of the Kyber Algorithm:

• Roberto Avanzi, ARM Limited (DE)
• Joppe Bos, NXP Semiconductors (BE)
• Léo Ducas, CWI Amsterdam (NL)
• Eike Kiltz, Ruhr University Bochum (DE)
• Tancrède Lepoint, SRI International (US)
• Vadim Lyubashevsky, IBM Research Zurich (CH)
• John M. Schanck, University of Waterloo (CA)
• Peter Schwabe, Radboud University (NL)
• Gregor Seiler, IBM Research Zurich (CH)
• Damien Stehle, ENS Lyon (FR)