add timingSafeEqual

Author: calvinmetcalf

README.md

@@ -25,6 +25,7 @@ Here is the subset that is currently implemented:
 * createECDH (secp256k1)
 * publicEncrypt/privateDecrypt (rsa)
 * privateEncrypt/publicDecrypt (rsa)
+* timingSafeEqual
 
 ## todo
 

index.js

@@ -63,6 +63,8 @@ var publicEncrypt = require('public-encrypt')
   exports[key] = publicEncrypt[key]
 })
 
+exports.timingSafeEqual = require('timing-safe-equal')
+
 // the least I can do is make error messages for the rest of the node.js/crypto api.
 ;[
   'createCredentials'

package.json

@@ -27,7 +27,8 @@
     "inherits": "^2.0.1",
     "pbkdf2": "^3.0.3",
     "public-encrypt": "^4.0.0",
-    "randombytes": "^2.0.0"
+    "randombytes": "^2.0.0",
+    "timing-safe-equal": "^1.0.0"
   },
   "devDependencies": {
     "hash-test-vectors": "~1.3.2",

test/index.js

@@ -12,6 +12,7 @@ try {
   require('./public-encrypt')
   require('./random-bytes')
   require('./sign')
+  require('./timing-safe-equal')
 } catch (e) {
   console.log('no secure rng avaiable')
 }

test/timing-safe-equal.js

@@ -0,0 +1,28 @@
+var test = require('tape')
+var timingSafeEqual = require('timing-safe-equal/browser')
+test('timingSafeEqual', function (t) {
+  t.plan(5)
+  t.strictEqual(
+    timingSafeEqual(Buffer.from('foo'), Buffer.from('foo')),
+    true,
+    'should consider equal strings to be equal'
+  )
+
+  t.strictEqual(
+    timingSafeEqual(Buffer.from('foo'), Buffer.from('bar')),
+    false,
+    'should consider unequal strings to be unequal'
+  )
+
+  t.throws(function () {
+    timingSafeEqual(Buffer.from([1, 2, 3]), Buffer.from([1, 2]))
+  }, 'should throw when given buffers with different lengths')
+
+  t.throws(function () {
+    timingSafeEqual('not a buffer', Buffer.from([1, 2]))
+  }, 'should throw if the first argument is not a buffer')
+
+  t.throws(function () {
+    timingSafeEqual(Buffer.from([1, 2]), 'not a buffer')
+  }, 'should throw if the second argument is not a buffer')
+})