feat(ecdh): use node core instead of webcrypto-ossl

package.json

@@ -7,6 +7,7 @@
     "node-webcrypto-ossl": false,
     "./src/crypto/webcrypto.js": "./src/crypto/webcrypto-browser.js",
     "./src/crypto/hmac.js": "./src/crypto/hmac-browser.js",
+    "./src/crypto/ecdh.js": "./src/crypto/ecdh-browser.js",
     "./src/crypto/ciphers.js": "./src/crypto/ciphers-browser.js"
   },
   "scripts": {
@@ -67,4 +68,4 @@
     "greenkeeperio-bot <support@greenkeeper.io>",
     "nikuda <nikuda@gmail.com>"
   ]
-}
+}

src/crypto/ecdh-browser.js

@@ -0,0 +1,129 @@
+'use strict'
+
+const crypto = require('./webcrypto')()
+const nodeify = require('nodeify')
+const BN = require('asn1.js').bignum
+
+const util = require('./util')
+const toBase64 = util.toBase64
+const toBn = util.toBn
+
+const bits = {
+  'P-256': 256,
+  'P-384': 384,
+  'P-521': 521
+}
+
+exports.generateEphmeralKeyPair = function (curve, callback) {
+  nodeify(crypto.subtle.generateKey(
+    {
+      name: 'ECDH',
+      namedCurve: curve
+    },
+    true,
+    ['deriveBits']
+  ).then((pair) => {
+    // forcePrivate is used for testing only
+    const genSharedKey = (theirPub, forcePrivate, cb) => {
+      if (typeof forcePrivate === 'function') {
+        cb = forcePrivate
+        forcePrivate = undefined
+      }
+
+      let privateKey
+
+      if (forcePrivate) {
+        privateKey = crypto.subtle.importKey(
+          'jwk',
+          unmarshalPrivateKey(curve, forcePrivate),
+          {
+            name: 'ECDH',
+            namedCurve: curve
+          },
+          false,
+          ['deriveBits']
+        )
+      } else {
+        privateKey = Promise.resolve(pair.privateKey)
+      }
+
+      const keys = Promise.all([
+        crypto.subtle.importKey(
+          'jwk',
+          unmarshalPublicKey(curve, theirPub),
+          {
+            name: 'ECDH',
+            namedCurve: curve
+          },
+          false,
+          []
+        ),
+        privateKey
+      ])
+
+      nodeify(keys.then((keys) => crypto.subtle.deriveBits(
+        {
+          name: 'ECDH',
+          namedCurve: curve,
+          public: keys[0]
+        },
+        keys[1],
+        bits[curve]
+      )).then((bits) => Buffer.from(bits)), cb)
+    }
+
+    return crypto.subtle.exportKey(
+      'jwk',
+      pair.publicKey
+    ).then((publicKey) => {
+      return {
+        key: marshalPublicKey(publicKey),
+        genSharedKey
+      }
+    })
+  }), callback)
+}
+
+const curveLengths = {
+  'P-256': 32,
+  'P-384': 48,
+  'P-521': 66
+}
+
+// Marshal converts a jwk encodec ECDH public key into the
+// form specified in section 4.3.6 of ANSI X9.62. (This is the format
+// go-ipfs uses)
+function marshalPublicKey (jwk) {
+  const byteLen = curveLengths[jwk.crv]
+
+  return Buffer.concat([
+    Buffer([4]), // uncompressed point
+    toBn(jwk.x).toBuffer('be', byteLen),
+    toBn(jwk.y).toBuffer('be', byteLen)
+  ], 1 + byteLen * 2)
+}
+
+// Unmarshal converts a point, serialized by Marshal, into an jwk encoded key
+function unmarshalPublicKey (curve, key) {
+  const byteLen = curveLengths[curve]
+
+  if (!key.slice(0, 1).equals(Buffer([4]))) {
+    throw new Error('Invalid key format')
+  }
+  const x = new BN(key.slice(1, byteLen + 1))
+  const y = new BN(key.slice(1 + byteLen))
+
+  return {
+    kty: 'EC',
+    crv: curve,
+    x: toBase64(x),
+    y: toBase64(y),
+    ext: true
+  }
+}
+
+function unmarshalPrivateKey (curve, key) {
+  const result = unmarshalPublicKey(curve, key.public)
+  result.d = toBase64(new BN(key.private))
+  return result
+}

src/crypto/ecdh.js

@@ -1,101 +1,41 @@
 'use strict'
 
-const crypto = require('./webcrypto')()
-const nodeify = require('nodeify')
-const BN = require('asn1.js').bignum
+const crypto = require('crypto')
+const setImmediate = require('async/setImmediate')
 
-const util = require('./util')
-const toBase64 = util.toBase64
-const toBn = util.toBn
+const curves = {
+  'P-256': 'prime256v1',
+  'P-384': 'secp384r1',
+  'P-521': 'secp521r1'
+}
 
 exports.generateEphmeralKeyPair = function (curve, callback) {
-  nodeify(crypto.subtle.generateKey(
-    {
-      name: 'ECDH',
-      namedCurve: curve
-    },
-    true,
-    ['deriveBits']
-  ).then((pair) => {
-    // forcePrivate is used for testing only
-    const genSharedKey = (theirPub, forcePrivate, cb) => {
+  if (!curves[curve]) {
+    return callback(new Error(`Unkown curve: ${curve}`))
+  }
+  const ecdh = crypto.createECDH(curves[curve])
+  ecdh.generateKeys()
+
+  setImmediate(() => callback(null, {
+    key: ecdh.getPublicKey(),
+    genSharedKey (theirPub, forcePrivate, cb) {
       if (typeof forcePrivate === 'function') {
         cb = forcePrivate
-        forcePrivate = undefined
+        forcePrivate = null
       }
 
-      const privateKey = forcePrivate || pair.privateKey
-      nodeify(crypto.subtle.importKey(
-        'jwk',
-        unmarshalPublicKey(curve, theirPub),
-        {
-          name: 'ECDH',
-          namedCurve: curve
-        },
-        false,
-        []
-      ).then((publicKey) => {
-        return crypto.subtle.deriveBits(
-          {
-            name: 'ECDH',
-            namedCurve: curve,
-            public: publicKey
-          },
-          privateKey,
-          256
-        )
-      }).then((bits) => {
-        // return p.derive(pub.getPublic()).toBuffer('be')
-        return Buffer.from(bits)
-      }), cb)
+      if (forcePrivate) {
+        ecdh.setPrivateKey(forcePrivate.private)
+      }
+
+      let secret
+      try {
+        secret = ecdh.computeSecret(theirPub)
+      } catch (err) {
+        return cb(err)
+      }
+
+      setImmediate(() => cb(null, secret))
     }
-
-    return crypto.subtle.exportKey(
-      'jwk',
-      pair.publicKey
-    ).then((publicKey) => {
-      return {
-        key: marshalPublicKey(publicKey),
-        genSharedKey
-      }
-    })
-  }), callback)
-}
-
-const curveLengths = {
-  'P-256': 32,
-  'P-384': 48,
-  'P-521': 66
-}
-
-// Marshal converts a jwk encodec ECDH public key into the
-// form specified in section 4.3.6 of ANSI X9.62. (This is the format
-// go-ipfs uses)
-function marshalPublicKey (jwk) {
-  const byteLen = curveLengths[jwk.crv]
-
-  return Buffer.concat([
-    Buffer([4]), // uncompressed point
-    toBn(jwk.x).toBuffer('be', byteLen),
-    toBn(jwk.y).toBuffer('be', byteLen)
-  ], 1 + byteLen * 2)
-}
-
-// Unmarshal converts a point, serialized by Marshal, into an jwk encoded key
-function unmarshalPublicKey (curve, key) {
-  const byteLen = curveLengths[curve]
-
-  if (!key.slice(0, 1).equals(Buffer([4]))) {
-    throw new Error('Invalid key format')
-  }
-  const x = new BN(key.slice(1, byteLen + 1))
-  const y = new BN(key.slice(1 + byteLen))
-
-  return {
-    kty: 'EC',
-    crv: curve,
-    x: toBase64(x),
-    y: toBase64(y),
-    ext: true
-  }
+  }))
 }

test/ephemeral-keys.spec.js

@@ -14,6 +14,11 @@ const lengths = {
   'P-384': 97,
   'P-521': 133
 }
+const secretLengths = {
+  'P-256': 32,
+  'P-384': 48,
+  'P-521': 66
+}
 
 describe('generateEphemeralKeyPair', () => {
   curves.forEach((curve) => {
@@ -28,7 +33,7 @@ describe('generateEphemeralKeyPair', () => {
 
         keys[0].genSharedKey(keys[1].key, (err, shared) => {
           expect(err).to.not.exist
-          expect(shared).to.have.length(32)
+          expect(shared).to.have.length(secretLengths[curve])
           done()
         })
       })
@@ -39,12 +44,29 @@ describe('generateEphemeralKeyPair', () => {
     it('generates a shared secret', (done) => {
       const curve = fixtures.curve
 
-      crypto.generateEphemeralKeyPair(curve, (err, alice) => {
+      parallel([
+        (cb) => crypto.generateEphemeralKeyPair(curve, cb),
+        (cb) => crypto.generateEphemeralKeyPair(curve, cb)
+      ], (err, res) => {
         expect(err).to.not.exist
+        const alice = res[0]
+        const bob = res[1]
+        bob.key = fixtures.bob.public
 
-        alice.genSharedKey(fixtures.bob.public, (err, s1) => {
+        parallel([
+          (cb) => alice.genSharedKey(bob.key, cb),
+          (cb) => bob.genSharedKey(alice.key, fixtures.bob, cb)
+        ], (err, secrets) => {
           expect(err).to.not.exist
-          expect(s1).to.have.length(32)
+
+          expect(
+            secrets[0]
+          ).to.be.eql(
+            secrets[1]
+          )
+
+          expect(secrets[0]).to.have.length(32)
+
           done()
         })
       })

test/fixtures/go-elliptic-key.js

@@ -3,9 +3,9 @@
 module.exports = {
   curve: 'P-256',
   bob: {
-    private: [
+    private: new Buffer([
       181, 217, 162, 151, 225, 36, 53, 253, 107, 66, 27, 27, 232, 72, 0, 0, 103, 167, 84, 62, 203, 91, 97, 137, 131, 193, 230, 126, 98, 242, 216, 170
-    ],
+    ]),
     public: new Buffer([
       4, 53, 59, 128, 56, 162, 250, 72, 141, 206, 117, 232, 57, 96, 39, 39, 247, 7, 27, 57, 251, 232, 120, 186, 21, 239, 176, 139, 195, 129, 125, 85, 11, 188, 191, 32, 227, 0, 6, 163, 101, 68, 208, 1, 43, 131, 124, 112, 102, 91, 104, 79, 16, 119, 152, 208, 4, 147, 155, 83, 20, 146, 104, 55, 90
     ])