feat(keys): add Ed25519 support for signing & verification

Closes #43

package.json

@@ -42,6 +42,7 @@
     "pem-jwk": "^1.5.1",
     "protocol-buffers": "^3.2.1",
     "rsa-pem-to-jwk": "^1.1.3",
+    "tweetnacl": "^0.14.5",
     "webcrypto-shim": "github:dignifiedquire/webcrypto-shim#master"
   },
   "devDependencies": {
@@ -75,4 +76,4 @@
     "Richard Littauer <richard.littauer@gmail.com>",
     "nikuda <nikuda@gmail.com>"
   ]
-}
+}

src/crypto.js

@@ -5,3 +5,4 @@ exports.hmac = require('./crypto/hmac')
 exports.ecdh = require('./crypto/ecdh')
 exports.aes = require('./crypto/aes')
 exports.rsa = require('./crypto/rsa')
+exports.ed25519 = require('./crypto/ed25519')

src/crypto.proto.js

@@ -2,6 +2,7 @@
 
 module.exports = `enum KeyType {
   RSA = 0;
+  Ed25519 = 1;
 }
 
 message PublicKey {

src/crypto/ed25519.js

@@ -0,0 +1,34 @@
+'use strict'
+
+const nacl = require('tweetnacl')
+const setImmediate = require('async/setImmediate')
+
+exports.publicKeyLength = nacl.sign.publicKeyLength
+exports.privateKeyLength = nacl.sign.secretKeyLength
+
+exports.generateKey = function (callback) {
+  const done = (err, res) => setImmediate(() => {
+    callback(err, res)
+  })
+
+  let keys
+  try {
+    keys = nacl.sign.keyPair()
+  } catch (err) {
+    done(err)
+    return
+  }
+  done(null, keys)
+}
+
+exports.hashAndSign = function (key, msg, callback) {
+  setImmediate(() => {
+    callback(null, Buffer.from(nacl.sign.detached(msg, key)))
+  })
+}
+
+exports.hashAndVerify = function (key, sig, msg, callback) {
+  setImmediate(() => {
+    callback(null, nacl.sign.detached.verify(msg, sig, key))
+  })
+}

src/index.js

@@ -9,6 +9,8 @@ exports.aes = c.aes
 exports.webcrypto = c.webcrypto
 
 const keys = exports.keys = require('./keys')
+const KEY_TYPES = ['rsa', 'ed25519']
+
 exports.keyStretcher = require('./key-stretcher')
 exports.generateEphemeralKeyPair = require('./ephemeral-keys')
 
@@ -30,6 +32,8 @@ exports.unmarshalPublicKey = (buf) => {
   switch (decoded.Type) {
     case pbm.KeyType.RSA:
       return keys.rsa.unmarshalRsaPublicKey(decoded.Data)
+    case pbm.KeyType.Ed25519:
+      return keys.ed25519.unmarshalEd25519PublicKey(decoded.Data)
     default:
       throw new Error('invalid or unsupported key type')
   }
@@ -38,9 +42,7 @@ exports.unmarshalPublicKey = (buf) => {
 // Converts a public key object into a protobuf serialized public key
 exports.marshalPublicKey = (key, type) => {
   type = (type || 'rsa').toLowerCase()
-
-  // for now only rsa is supported
-  if (type !== 'rsa') {
+  if (KEY_TYPES.indexOf(type) < 0) {
     throw new Error('invalid or unsupported key type')
   }
 
@@ -55,6 +57,8 @@ exports.unmarshalPrivateKey = (buf, callback) => {
   switch (decoded.Type) {
     case pbm.KeyType.RSA:
       return keys.rsa.unmarshalRsaPrivateKey(decoded.Data, callback)
+    case pbm.KeyType.Ed25519:
+      return keys.ed25519.unmarshalEd25519PrivateKey(decoded.Data, callback)
     default:
       callback(new Error('invalid or unsupported key type'))
   }
@@ -63,9 +67,7 @@ exports.unmarshalPrivateKey = (buf, callback) => {
 // Converts a private key object into a protobuf serialized private key
 exports.marshalPrivateKey = (key, type) => {
   type = (type || 'rsa').toLowerCase()
-
-  // for now only rsa is supported
-  if (type !== 'rsa') {
+  if (KEY_TYPES.indexOf(type) < 0) {
     throw new Error('invalid or unsupported key type')
   }
 

src/keys/ed25519.js

@@ -0,0 +1,141 @@
+'use strict'
+
+const multihashing = require('multihashing-async')
+const protobuf = require('protocol-buffers')
+
+const crypto = require('../crypto').ed25519
+const pbm = protobuf(require('../crypto.proto'))
+
+class Ed25519PublicKey {
+  constructor (key) {
+    this._key = ensureKey(key, crypto.publicKeyLength)
+  }
+
+  verify (data, sig, callback) {
+    ensure(callback)
+    crypto.hashAndVerify(this._key, sig, data, callback)
+  }
+
+  marshal () {
+    return Buffer.from(this._key)
+  }
+
+  get bytes () {
+    return pbm.PublicKey.encode({
+      Type: pbm.KeyType.Ed25519,
+      Data: this.marshal()
+    })
+  }
+
+  equals (key) {
+    return this.bytes.equals(key.bytes)
+  }
+
+  hash (callback) {
+    ensure(callback)
+    multihashing(this.bytes, 'sha2-256', callback)
+  }
+}
+
+class Ed25519PrivateKey {
+  // key       - 64 byte Uint8Array or Buffer containing private key
+  // publicKey - 32 byte Uint8Array or Buffer containing public key
+  constructor (key, publicKey) {
+    this._key = ensureKey(key, crypto.privateKeyLength)
+    this._publicKey = ensureKey(publicKey, crypto.publicKeyLength)
+  }
+
+  sign (message, callback) {
+    ensure(callback)
+    crypto.hashAndSign(this._key, message, callback)
+  }
+
+  get public () {
+    if (!this._publicKey) {
+      throw new Error('public key not provided')
+    }
+
+    return new Ed25519PublicKey(this._publicKey)
+  }
+
+  marshal () {
+    return Buffer.concat([Buffer.from(this._key), Buffer.from(this._publicKey)])
+  }
+
+  get bytes () {
+    return pbm.PrivateKey.encode({
+      Type: pbm.KeyType.Ed25519,
+      Data: this.marshal()
+    })
+  }
+
+  equals (key) {
+    return this.bytes.equals(key.bytes)
+  }
+
+  hash (callback) {
+    ensure(callback)
+    multihashing(this.bytes, 'sha2-256', callback)
+  }
+}
+
+function unmarshalEd25519PrivateKey (bytes, callback) {
+  try {
+    bytes = ensureKey(bytes, crypto.privateKeyLength + crypto.publicKeyLength)
+  } catch (err) {
+    return callback(err)
+  }
+  const privateKeyBytes = bytes.slice(0, crypto.privateKeyLength)
+  const publicKeyBytes = bytes.slice(crypto.privateKeyLength, bytes.length)
+  callback(null, new Ed25519PrivateKey(privateKeyBytes, publicKeyBytes))
+}
+
+function unmarshalEd25519PublicKey (bytes) {
+  bytes = ensureKey(bytes, crypto.publicKeyLength)
+  return new Ed25519PublicKey(bytes)
+}
+
+function generateKeyPair (_bits, cb) {
+  if (cb === undefined && typeof _bits === 'function') {
+    cb = _bits
+  }
+
+  crypto.generateKey((err, keys) => {
+    if (err) {
+      return cb(err)
+    }
+    let privkey
+    try {
+      privkey = new Ed25519PrivateKey(keys.secretKey, keys.publicKey)
+    } catch (err) {
+      cb(err)
+      return
+    }
+
+    cb(null, privkey)
+  })
+}
+
+function ensure (cb) {
+  if (typeof cb !== 'function') {
+    throw new Error('callback is required')
+  }
+}
+
+function ensureKey (key, length) {
+  if (Buffer.isBuffer(key)) {
+    key = new Uint8Array(key)
+  }
+  if (!(key instanceof Uint8Array) || key.length !== length) {
+    throw new Error('Key must be a Uint8Array or Buffer of length ' + length)
+  }
+  return key
+}
+
+module.exports = {
+  Ed25519PublicKey,
+  Ed25519PrivateKey,
+  unmarshalEd25519PrivateKey,
+  unmarshalEd25519PublicKey,
+  generateKeyPair
+}

src/keys/index.js

@@ -1,5 +1,6 @@
 'use strict'
 
 module.exports = {
-  rsa: require('./rsa')
+  rsa: require('./rsa'),
+  ed25519: require('./ed25519')
 }

test/ed25519.spec.js

@@ -0,0 +1,194 @@
+/* eslint-env mocha */
+'use strict'
+
+const expect = require('chai').expect
+
+const crypto = require('../src')
+const ed25519 = crypto.keys.ed25519
+const fixtures = require('./fixtures/go-key-ed25519')
+
+describe('ed25519', () => {
+  let key
+  before((done) => {
+    crypto.generateKeyPair('Ed25519', 512, (err, _key) => {
+      if (err) return done(err)
+      key = _key
+      done()
+    })
+  })
+
+  it('generates a valid key', (done) => {
+    expect(
+      key
+    ).to.be.an.instanceof(
+      ed25519.Ed25519PrivateKey
+    )
+
+    key.hash((err, digest) => {
+      if (err) {
+        return done(err)
+      }
+
+      expect(digest).to.have.length(34)
+      done()
+    })
+  })
+
+  it('signs', (done) => {
+    const text = crypto.randomBytes(512)
+
+    key.sign(text, (err, sig) => {
+      if (err) {
+        return done(err)
+      }
+
+      key.public.verify(text, sig, (err, res) => {
+        if (err) {
+          return done(err)
+        }
+
+        expect(res).to.be.eql(true)
+        done()
+      })
+    })
+  })
+
+  it('encoding', (done) => {
+    const keyMarshal = key.marshal()
+    ed25519.unmarshalEd25519PrivateKey(keyMarshal, (err, key2) => {
+      if (err) {
+        return done(err)
+      }
+      const keyMarshal2 = key2.marshal()
+
+      expect(
+        keyMarshal
+      ).to.be.eql(
+        keyMarshal2
+      )
+
+      const pk = key.public
+      const pkMarshal = pk.marshal()
+      const pk2 = ed25519.unmarshalEd25519PublicKey(pkMarshal)
+      const pkMarshal2 = pk2.marshal()
+
+      expect(
+        pkMarshal
+      ).to.be.eql(
+        pkMarshal2
+      )
+      done()
+    })
+  })
+
+  describe('key equals', () => {
+    it('equals itself', () => {
+      expect(
+        key.equals(key)
+      ).to.be.eql(
+        true
+      )
+
+      expect(
+        key.public.equals(key.public)
+      ).to.be.eql(
+        true
+      )
+    })
+
+    it('not equals other key', (done) => {
+      crypto.generateKeyPair('Ed25519', 512, (err, key2) => {
+        if (err) return done(err)
+
+        expect(
+          key.equals(key2)
+        ).to.be.eql(
+          false
+        )
+
+        expect(
+          key2.equals(key)
+        ).to.be.eql(
+          false
+        )
+
+        expect(
+          key.public.equals(key2.public)
+        ).to.be.eql(
+          false
+        )
+
+        expect(
+          key2.public.equals(key.public)
+        ).to.be.eql(
+          false
+        )
+        done()
+      })
+    })
+  })
+
+  it('sign and verify', (done) => {
+    const data = new Buffer('hello world')
+    key.sign(data, (err, sig) => {
+      if (err) {
+        return done(err)
+      }
+
+      key.public.verify(data, sig, (err, valid) => {
+        if (err) {
+          return done(err)
+        }
+        expect(valid).to.be.eql(true)
+        done()
+      })
+    })
+  })
+
+  it('fails to verify for different data', (done) => {
+    const data = new Buffer('hello world')
+    key.sign(data, (err, sig) => {
+      if (err) {
+        return done(err)
+      }
+
+      key.public.verify(new Buffer('hello'), sig, (err, valid) => {
+        if (err) {
+          return done(err)
+        }
+        expect(valid).to.be.eql(false)
+        done()
+      })
+    })
+  })
+
+  describe('go interop', () => {
+    let privateKey
+    before((done) => {
+      crypto.unmarshalPrivateKey(fixtures.verify.privateKey, (err, key) => {
+        expect(err).to.not.exist
+        privateKey = key
+        done()
+      })
+    })
+
+    it('verifies with data from go', (done) => {
+      const key = crypto.unmarshalPublicKey(fixtures.verify.publicKey)
+
+      key.verify(fixtures.verify.data, fixtures.verify.signature, (err, ok) => {
+        if (err) throw err
+        expect(err).to.not.exist
+        expect(ok).to.be.eql(true)
+        done()
+      })
+    })
+
+    it('generates the same signature as go', (done) => {
+      privateKey.sign(fixtures.verify.data, (err, sig) => {
+        expect(err).to.not.exist
+        expect(sig).to.deep.equal(fixtures.verify.signature)
+        done()
+      })
+    })
+  })
+})

test/fixtures/go-key-ed25519.js

@@ -0,0 +1,28 @@
+'use strict'
+
+module.exports = {
+  // These were generated in a gore (https://github.com/motemen/gore) repl session:
+  //
+  // :import github.com/libp2p/go-libp2p-crypto
+  // :import crypto/rand
+  // priv, pub, err := crypto.GenerateEd25519Key(rand.Reader)
+  // pubkeyBytes, err := pub.Bytes()
+  // privkeyBytes, err := priv.Bytes()
+  // data := []byte("hello! and welcome to some awesome crypto primitives")
+  // sig, err := priv.Sign(data)
+  //
+  // :import io/ioutil
+  // ioutil.WriteFile("/tmp/pubkey_go.bin", pubkeyBytes, 0644)
+  // // etc..
+  //
+  // Then loaded into a node repl and dumped to arrays with:
+  //
+  // var pubkey = Array.from(fs.readFileSync('/tmp/pubkey_go.bin'))
+  // console.log(JSON.stringify(pubkey))
+  verify: {
+    privateKey: Buffer.from([8, 1, 18, 96, 201, 208, 1, 110, 176, 16, 230, 37, 66, 184, 149, 252, 78, 56, 206, 136, 2, 38, 118, 152, 226, 197, 117, 200, 54, 189, 156, 218, 184, 7, 118, 57, 233, 49, 221, 97, 164, 158, 241, 129, 73, 166, 225, 255, 193, 118, 22, 84, 55, 15, 249, 168, 225, 180, 198, 191, 14, 75, 187, 243, 150, 91, 232, 37, 233, 49, 221, 97, 164, 158, 241, 129, 73, 166, 225, 255, 193, 118, 22, 84, 55, 15, 249, 168, 225, 180, 198, 191, 14, 75, 187, 243, 150, 91, 232, 37]),
+    publicKey: Buffer.from([8, 1, 18, 32, 233, 49, 221, 97, 164, 158, 241, 129, 73, 166, 225, 255, 193, 118, 22, 84, 55, 15, 249, 168, 225, 180, 198, 191, 14, 75, 187, 243, 150, 91, 232, 37]),
+    data: Buffer.from([104, 101, 108, 108, 111, 33, 32, 97, 110, 100, 32, 119, 101, 108, 99, 111, 109, 101, 32, 116, 111, 32, 115, 111, 109, 101, 32, 97, 119, 101, 115, 111, 109, 101, 32, 99, 114, 121, 112, 116, 111, 32, 112, 114, 105, 109, 105, 116, 105, 118, 101, 115]),
+    signature: Buffer.from([7, 230, 175, 164, 228, 58, 78, 208, 62, 243, 73, 142, 83, 195, 176, 217, 166, 62, 41, 165, 168, 164, 75, 179, 163, 86, 102, 32, 18, 84, 150, 237, 39, 207, 213, 20, 134, 237, 50, 41, 176, 183, 229, 133, 38, 255, 42, 228, 68, 186, 100, 14, 175, 156, 243, 118, 125, 125, 120, 212, 124, 103, 252, 12])
+  }
+}