hpke-js

A TypeScript Hybrid Public Key Encryption (HPKE) implementation build on top of Web Cryptography API. This library works on both web browsers and Node.js (currently, Deno is not supported).

API Documentation

Index

Supported Features
Warnings and Restrictions
Installation
Usage
Contributing
References

Supported Features

HPKE Modes

Base	PSK	Auth	AuthPSK
✅	✅	✅	✅

Key Encapsulation Machanisms (KEMs)

KEMs	Browser	Node.js
DHKEM (P-256, HKDF-SHA256)	✅	✅
DHKEM (P-384, HKDF-SHA384)	✅	✅
DHKEM (P-521, HKDF-SHA512)	✅	✅
DHKEM (X25519, HKDF-SHA256)	✅	✅
DHKEM (X448, HKDF-SHA512)	✅	✅

Key Derivation Functions (KDFs)

KDFs	Browser	Node.js
HKDF-SHA256	✅	✅
HKDF-SHA384	✅	✅
HKDF-SHA512	✅	✅

Authenticated Encryption with Associated Data (AEAD) Functions

AEADs	Browser	Node.js
AES-128-GCM	✅	✅
AES-256-GCM	✅	✅
ChaCha20Poly1305	✅	✅
Export Only	✅	✅

Warnings and Restrictions

Although this library has been passed the following test vectors, it has not been formally audited.
- RFC9180 official test vectors provided on github.com/cfrg/draft-irtf-cfrg-hpke
- Test vectors for ECDH(P-256, P-384 and P-521) and X25519 key validation provided on Project Wycheproof
The upper limit of the AEAD sequence number is further rounded to JavaScript Number.MAX_SAFE_INTEGER (2^53 - 1).

Installation

Using npm:

npm install hpke-js

Using unpkg CDN:

<!-- use the latest stable version -->
<script src="https://unpkg.com/hpke-js/dist/hpke.min.js"></script>

<!-- use a specific version -->
<script src="https://unpkg.com/hpke-js@0.9.0/dist/hpke.min.js"></script>

Using jsDelivr CDN:

<!-- use the latest stable version -->
<script src="https://cdn.jsdelivr.net/npm/hpke-js/dist/hpke.min.js"></script>

<!-- use a specific version -->
<script src="https://cdn.jsdelivr.net/npm/hpke-js@0.9.0/dist/hpke.min.js"></script>

Usage

This section shows some typical usage examples.

Base mode

On browser:

<html>
  <head></head>
  <body>
    <script src="https://unpkg.com/hpke-js/dist/hpke.min.js"></script>
    <script type="text/javascript">

      async function doHpke() {

        // the global name is 'hkpe'
        const suite = new hpke.CipherSuite({
          kem: hpke.Kem.DhkemP256HkdfSha256,
          kdf: hpke.Kdf.HkdfSha256,
          aead: hpke.Aead.Aes128Gcm
        });
 
        const rkp = await suite.generateKeyPair();
      
        const sender = await suite.createSenderContext({
          recipientPublicKey: rkp.publicKey
        });
      
        const recipient = await suite.createRecipientContext({
          recipientKey: rkp,
          enc: sender.enc,
        });
      
        // encrypt
        const ct = await sender.seal(new TextEncoder().encode('hello world!'));
      
        // decrypt
        const pt = await recipient.open(ct);

        // hello world!
        alert(new TextDecoder().decode(pt));
      }
      
    </script>
    <button type="button" onclick="doHpke()">do HPKE</button>
  </body>
</html>

On Node.js:

const { Kem, Kdf, Aead, CipherSuite } = require('hpke-js');

async function doHpke() {

  // setup
  const suite = new CipherSuite({
    kem: Kem.DhkemP256HkdfSha256,
    kdf: Kdf.HkdfSha256,
    aead: Aead.Aes128Gcm
  });

  const rkp = await suite.generateKeyPair();

  const sender = await suite.createSenderContext({
    recipientPublicKey: rkp.publicKey
  });

  const recipient = await suite.createRecipientContext({
    recipientKey: rkp,
    enc: sender.enc,
  });

  // encrypt
  const ct = await sender.seal(new TextEncoder().encode('my-secret-message'));

  // decrypt
  const pt = await recipient.open(ct);

  console.log('decrypted: ', new TextDecoder().decode(pt));
  // decrypted: my-secret-message
}

doHpke();

Base mode with Single-Shot APIs

On Node.js:

const { Kem, Kdf, Aead, CipherSuite } = require('hpke-js');

async function doHpke() {

  // setup
  const suite = new CipherSuite({
    kem: Kem.DhkemP256HkdfSha256,
    kdf: Kdf.HkdfSha256,
    aead: Aead.Aes128Gcm
  });

  const rkp = await suite.generateKeyPair();
  const pt = new TextEncoder().encode('my-secret-message'),

  // encrypt
  const { ct, enc } = await suite.seal({ recipientPublicKey: rkp.publicKey }, pt);

  // decrypt
  const pt = await suite.open({ recipientKey: rkp, enc: enc }, ct);

  console.log('decrypted: ', new TextDecoder().decode(pt));
  // decrypted: my-secret-message
}

doHpke();

Base mode with bidirectional encryption

On Node.js:

const { Kem, Kdf, Aead, CipherSuite } = require('hpke-js');

const te = new TextEncoder();
const td = new TextDecoder();

async function doHpke() {

  // setup
  const suite = new CipherSuite({
    kem: Kem.DhkemP256HkdfSha256,
    kdf: Kdf.HkdfSha256,
    aead: Aead.Aes128Gcm,
  });
  const rkp = await suite.generateKeyPair();

  const sender = await suite.createSenderContext({
    recipientPublicKey: rkp.publicKey,
  });

  const recipient = await suite.createRecipientContext({
    recipientKey: rkp,
    enc: sender.enc,
  });

  // setup bidirectional encryption
  await sender.setupBidirectional(te.encode('seed-for-key'), te.encode('seed-for-nonce'));
  await recipient.setupBidirectional(te.encode('seed-for-key'), te.encode('seed-for-nonce'));

  // encrypt
  const ct = await sender.seal(te.encode('my-secret-message-s'));

  // decrypt
  const pt = await recipient.open(ct);

  console.log('recipient decrypted: ', td.decode(pt));
  // decrypted: my-secret-message-s

  // encrypt reversely
  const rct = await recipient.seal(te.encode('my-secret-message-r'));

  // decrypt reversely
  const rpt = await sender.open(rct);

  console.log('sender decrypted: ', td.decode(rpt));
  // decrypted: my-secret-message-r
}

doHpke();

Base mode with export-only AEAD

On Node.js:

  const suite = new CipherSuite({
    kem: Kem.DhkemP256HkdfSha256,
    kdf: Kdf.HkdfSha256,
    aead: Aead.ExportOnly,
  });

  const rkp = await suite.generateKeyPair();

  const sender = await suite.createSenderContext({
    recipientPublicKey: rkp.publicKey,
  });

  const recipient = await suite.createRecipientContext({
    recipientKey: rkp,
    enc: sender.enc,
  });

  const te = new TextEncoder();

  // export
  const pskS = sender.export(te.encode('jugemujugemu'), 32);
  const pskR = recipient.export(te.encode('jugemujugemu'), 32);
  // pskR === pskS
}

doHpke();

PSK mode

On Node.js:

const { Kem, Kdf, Aead, CipherSuite } = require('hpke-js');

async function doHpke() {
  // setup
  const suite = new CipherSuite({
    kem: Kem.DhkemP256HkdfSha256,
    kdf: Kdf.HkdfSha256,
    aead: Aead.Aes128Gcm
  });

  const rkp = await suite.generateKeyPair();

  const sender = await suite.createSenderContext({
    recipientPublicKey: rkp.publicKey,
    psk: {
      id: new TextEncoder().encode('our-pre-shared-key-id'),
      // a PSK MUST have at least 32 bytes.
      key: new TextEncoder().encode('jugemujugemugokounosurikirekaija'),
    }
  });

  const recipient = await suite.createRecipientContext({
    recipientKey: rkp,
    enc: sender.enc,
    psk: {
      id: new TextEncoder().encode('our-pre-shared-key-id'),
      // a PSK MUST have at least 32 bytes.
      key: new TextEncoder().encode('jugemujugemugokounosurikirekaija'),
    }
  });

  // encrypt
  const ct = await sender.seal(new TextEncoder().encode('my-secret-message'));

  // decrypt
  const pt = await recipient.open(ct);

  console.log('decrypted: ', new TextDecoder().decode(pt));
  // decrypted: my-secret-message
}

doHpke();

Auth mode

On Node.js:

const { Kem, Kdf, Aead, CipherSuite } = require('hpke-js');

async function doHpke() {
  // setup
  const suite = new CipherSuite({
    kem: Kem.DhkemP256HkdfSha256,
    kdf: Kdf.HkdfSha256,
    aead: Aead.Aes128Gcm
  });

  const rkp = await suite.generateKeyPair();
  const skp = await suite.generateKeyPair();

  const sender = await suite.createSenderContext({
    recipientPublicKey: rkp.publicKey,
    senderKey: skp
  });

  const recipient = await suite.createRecipientContext({
    recipientKey: rkp,
    enc: sender.enc,
    senderPublicKey: skp.publicKey
  });

  // encrypt
  const ct = await sender.seal(new TextEncoder().encode('my-secret-message'));

  // decrypt
  const pt = await recipient.open(ct);

  console.log('decrypted: ', new TextDecoder().decode(pt));
  // decrypted: my-secret-message
}

doHpke();

AuthPSK mode

On Node.js:

const { Kem, Kdf, Aead, CipherSuite } = require('hpke-js');

async function doHpke() {
  // setup
  const suite = new CipherSuite({
    kem: Kem.DhkemP256HkdfSha256,
    kdf: Kdf.HkdfSha256,
    aead: Aead.Aes128Gcm
  });

  const rkp = await suite.generateKeyPair();
  const skp = await suite.generateKeyPair();

  const sender = await suite.createSenderContext({
    recipientPublicKey: rkp.publicKey,
    senderKey: skp,
    psk: {
      id: new TextEncoder().encode('our-pre-shared-key-id'),
      // a PSK MUST have at least 32 bytes.
      key: new TextEncoder().encode('jugemujugemugokounosurikirekaija'),
    }
  });

  const recipient = await suite.createRecipientContext({
    recipientKey: rkp,
    enc: sender.enc,
    senderPublicKey: skp.publicKey,
    psk: {
      id: new TextEncoder().encode('our-pre-shared-key-id'),
      // a PSK MUST have at least 32 bytes.
      key: new TextEncoder().encode('jugemujugemugokounosurikirekaija'),
    }
  });

  // encrypt
  const ct = await sender.seal(new TextEncoder().encode('my-secret-message'));

  // decrypt
  const pt = await recipient.open(ct);

  console.log('decrypted: ', new TextDecoder().decode(pt));
  // decrypted: my-secret-message
}

doHpke();

Contributing

We welcome all kind of contributions, filing issues, suggesting new features or sending PRs.

References

RFC9180: Hybrid Public Key Encryption