Merge branch 'add-pseudoRandomBytes' of https://github.com/plediii/crypto-browserify

Author: dominictarr

index.js

@@ -1,5 +1,6 @@
 'use strict';
-var rng = require('./rng')
+var rng = exports.rng = require('./rng')
+var prng = exports.prng = require('./prng');
 
 function error () {
   var m = [].slice.call(arguments).join(' ')
@@ -17,10 +18,19 @@ exports.createHmac = require('./create-hmac')
 exports.randomBytes = function(size, callback) {
   if (callback && callback.call) {
     try {
-      callback.call(this, undefined, new Buffer(rng(size)))
+      callback.call(this, undefined, rng(size))
     } catch (err) { callback(err) }
   } else {
-    return new Buffer(rng(size))
+    return rng(size)
+  }
+}
+exports.pseudoRandomBytes = function(size, callback) {
+  if (callback && callback.call) {
+    try {
+      callback.call(this, undefined, prng(size))
+    } catch (err) { callback(err) }
+  } else {
+    return prng(size)
   }
 }
 

prng.js

@@ -0,0 +1,27 @@
+'use strict';
+(function() {
+  var g = ('undefined' === typeof window ? global : window) || {}
+  var _crypto = (
+    g.crypto || g.msCrypto || require('crypto')
+  )
+  module.exports = function(size) {
+    // Modern Browsers
+    if(_crypto.getRandomValues) {
+      var bytes = new Buffer(size); //in browserify, this is an extended Uint8Array
+      /* This will not work in older browsers.
+       * See https://developer.mozilla.org/en-US/docs/Web/API/window.crypto.getRandomValues
+       */
+
+      _crypto.getRandomValues(bytes);
+      return bytes;
+    }
+    else if (_crypto.pseudoRandomBytes) {
+      return _crypto.pseudoRandomBytes(size)
+    }
+    else
+      throw new Error(
+        'pseudo random number generation not yet implemented for this browser\n'+
+        'use chrome, FireFox or Internet Explorer 11'
+      )
+  }
+}())

test/random-bytes.js

@@ -1,55 +1,60 @@
 var test = require('tape')
 var crypto = require('../')
 
-test('get error message', function (t) {
-
-  try {
-    var b = crypto.randomBytes(10)
-    t.ok(Buffer.isBuffer(b))
-    t.end()
-  } catch (err) {
-    t.ok(/not supported/.test(err.message), '"not supported"  is in error message')
-    t.end()
-  }
-
-})
-
-test('randomBytes', function (t) {
-    t.plan(5);
-    t.equal(crypto.randomBytes(10).length, 10);
-    t.ok(Buffer.isBuffer(crypto.randomBytes(10)))
-    crypto.randomBytes(10, function(ex, bytes) {
-        t.error(ex);
-        t.equal(bytes.length, 10);
-        t.ok(Buffer.isBuffer(bytes))
-        t.end();
+var randomBytesFunctions = ['randomBytes', 'pseudoRandomBytes'];
+for (var idx in randomBytesFunctions) {
+  // Both randomBytes and pseudoRandomBytes should provide the same interface
+  var randomBytesName = randomBytesFunctions[idx];
+  var randomBytes = crypto[randomBytesName]
+  test('get error message', function (t) {
+  
+    try {
+      var b = randomBytes(10)
+      t.ok(Buffer.isBuffer(b))
+      t.end()
+    } catch (err) {
+      t.ok(/not supported/.test(err.message), '"not supported"  is in error message')
+      t.end()
+    }
+  
+  })
+  
+  test(randomBytesName, function (t) {
+      t.plan(5);
+      t.equal(randomBytes(10).length, 10);
+      t.ok(Buffer.isBuffer(randomBytes(10)))
+      randomBytes(10, function(ex, bytes) {
+          t.error(ex);
+          t.equal(bytes.length, 10);
+          t.ok(Buffer.isBuffer(bytes))
+          t.end();
+    });
   });
-});
-
-test('randomBytes seem random', function (t) {
-
-  var L = 1000
-  var b = crypto.randomBytes(L)
-
-  var mean = [].reduce.call(b, function (a, b) { return a + b}, 0) / L
-
-  // test that the random numbers are plausably random.
-  // Math.random() will pass this, but this will catch
-  // terrible mistakes such as this blunder:
-  // https://github.com/dominictarr/crypto-browserify/commit/3267955e1df7edd1680e52aeede9a89506ed2464#commitcomment-7916835
-
-  // this doesn't check that the bytes are in a random *order*
-  // but it's better than nothing.
-
-  var expected = 256/2
-  var smean = Math.sqrt(mean)
-  //console.log doesn't work right on testling, *grumble grumble*
-  console.log(JSON.stringify([expected - smean, mean, expected + smean]))
-  t.ok(mean < expected + smean)
-  t.ok(mean > expected - smean)
-
-  t.end()
-
-})
-
+  
+  test(randomBytesName + ' seem random', function (t) {
+  
+    var L = 1000
+    var b = randomBytes(L)
+  
+    var mean = [].reduce.call(b, function (a, b) { return a + b}, 0) / L
+  
+    // test that the random numbers are plausably random.
+    // Math.random() will pass this, but this will catch
+    // terrible mistakes such as this blunder:
+    // https://github.com/dominictarr/crypto-browserify/commit/3267955e1df7edd1680e52aeede9a89506ed2464#commitcomment-7916835
+  
+    // this doesn't check that the bytes are in a random *order*
+    // but it's better than nothing.
+  
+    var expected = 256/2
+    var smean = Math.sqrt(mean)
+    //console.log doesn't work right on testling, *grumble grumble*
+    console.log(JSON.stringify([expected - smean, mean, expected + smean]))
+    t.ok(mean < expected + smean)
+    t.ok(mean > expected - smean)
+  
+    t.end()
+  
+  })
+}