@digitalcredentials/x25519-key-agreement-key-2020

X25519KeyAgreementKey2020 (@digitalcredentials/x25519-key-agreement-key-2020)

An X25519 (Curve25519) DH (Diffie-Hellman) key implementation to work with the X25519 2020 Crypto suite.

Table of Contents

• Security
• Background
• Install
• Usage
• Contribute
• Commercial Support
• License

Security

TBD

Background

(Forked from digitalbazaar/x25519-key-agreement-key-2020 v2.0.0 to provide TypeScript compatibility.)

For use with crypto-ld >= 5.0.

To actually perform encryption with those keys, we recommend you use the minimal-cipher library.

This is a low-level level library to generate and serialize X25519 (Curve25519) key pairs (uses nacl.box under the hood).

See also (related specs):

• Linked Data Proofs
• Linked Data Cryptographic Suite Registry

Install

Requires Node.js 12+

To install locally (for development):

git clone https://github.com/digitalcredentials/x25519-key-agreement-key-2020.git
cd x25519-key-agreement-key-2020
npm install

Usage

Importing:

const {X25519KeyAgreementKey2020} = require('@digitalcredentials/x25519-key-agreement-key-2020');

// Or, if you're testing code in the interactive Node CLI, right in this repo:
const {X25519KeyAgreementKey2020} = require('./');

Generating:

const keyPair = await X25519KeyAgreementKey2020.generate({
  controller: 'did:example:1234'
});
// ->
{
  "id": "did:example:1234#z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM",
  "controller": "did:example:1234",
  "type": "X25519KeyAgreementKey2020",
  "publicKeyMultibase": "z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM",
  "privateKeyMultibase": "z3weeMD56C1T347EmB6kYNS7trpQwjvtQCpCYRpqGz6mcemT"
}

Serializing just the public key:

keyPair.export({publicKey: true});
// ->
{
  "id": "did:example:1234#z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM",
  "controller": "did:example:1234",
  "type": "X25519KeyAgreementKey2020",
  "publicKeyMultibase": "z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM"
}

Serializing both the private and public key:

// a different key pair than the previous example
await keyPair.export({publicKey: true, privateKey: true})
// ->
{
  "id": "did:example:1234#z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM",
  "controller": "did:example:1234",
  "type": "X25519KeyAgreementKey2020",
  "publicKeyMultibase": "z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM",
  "privateKeyMultibase": "z3weeMD56C1T347EmB6kYNS7trpQwjvtQCpCYRpqGz6mcemT"
}

Deserializing:

// Loading public key only
const keyPair = await X25519KeyAgreementKey2020.from({
  "id": "did:example:1234#z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM",
  "controller": "did:example:1234",
  "type": "X25519KeyAgreementKey2020",
  "publicKeyMultibase": "z6LSeRSE5Em5oJpwdk3NBaLVERBS332ULC7EQq5EtMsmXhsM"
});

Contribute

See the contribute file!

PRs accepted.

If editing the Readme, please conform to the standard-readme specification.

License

• MIT License - DCC - TypeScript compatibility.
• New BSD License (3-clause) © 2020-2021 Digital Bazaar - Initial implementation.

Changelog

3.0.0 - 2022-09-08

Changed

• Replace internal ed25519 => x25519 conversion implementation such that only tweetnacl is used, allowing for ed2curve dependency to be removed.