random

...code from bitcore

index.js

@@ -17,6 +17,7 @@ privsec.hash = require('./lib/hash');
 privsec.point = require('./lib/point');
 privsec.privkey = require('./lib/privkey');
 privsec.pubkey = require('./lib/pubkey');
+privsec.random = require('./lib/random');
 
 //privsec.key = require('lib/key');
 //privsec.script = require('lib/script');

lib/random.js

@@ -0,0 +1,54 @@
+function Random() {
+};
+
+/* secure random bytes that sometimes throws an error due to lack of entropy */
+Random.getRandomBuffer = function(size) {
+  if (typeof process === 'undefined' || process.browser)
+    return Random.getRandomBufferBrowser(size);
+  else
+    return Random.getRandomBufferNode(size);
+};
+
+Random.getRandomBufferNode = function(size) {
+  var crypto = require('crypto');
+  return crypto.randomBytes(size);
+}
+
+Random.getRandomBufferBrowser = function(size) {
+  if (!window.crypto && !window.msCrypto)
+    throw new Error('random: window.crypto not available');
+
+  if (window.crypto && window.crypto.getRandomValues)
+    var crypto = window.crypto;
+  else if (window.msCrypto && window.msCrypto.getRandomValues) //internet explorer
+    var crypto = window.msCrypto;
+  else
+    throw new Error('random: window.crypto.getRandomValues not available');
+
+  var bbuf = new Uint8Array(size);
+  crypto.getRandomValues(bbuf);
+  var buf = new Buffer(bbuf);
+
+  return buf;
+};
+
+/* insecure random bytes, but it never fails */
+Random.getPseudoRandomBuffer = function(size) {
+  var b32 = 0x100000000;
+  var b = new Buffer(size);
+
+  for (var i = 0; i <= size; i++) {
+    var j = Math.floor(i / 4);
+    var k = i - j * 4;
+    if (k == 0) {
+      r = Math.random() * b32;
+      b[i] = r & 0xff;
+    } else {
+      b[i] = (r = r >>> 8) & 0xff;
+    }
+  }
+
+  return b;
+};
+
+module.exports = Random;

test/test.random.js

@@ -0,0 +1,61 @@
+var should = require('chai').should();
+var Random = require('../lib/random');
+
+describe('Random', function() {
+
+  describe('getRandomBuffer', function() {
+
+    it('should return a buffer', function() {
+      var bytes = Random.getRandomBuffer(8);
+      bytes.length.should.equal(8);
+      Buffer.isBuffer(bytes).should.equal(true);
+    });
+
+    it('should not equate two 256 bit random buffers', function() {
+      var bytes1 = Random.getRandomBuffer(32);
+      var bytes2 = Random.getRandomBuffer(32);
+      bytes1.toString('hex').should.not.equal(bytes2.toString('hex'));
+    });
+
+    it('should generate 1000 8 byte buffers in a row that are not equal', function() {
+      var bufs = [];
+      for (var i = 0; i < 100; i++)
+        bufs[i] = Random.getRandomBuffer(8);
+      for (var i = 0; i < 100; i++)
+        for (var j = i + 1; j < 100; j++)
+          bufs[i].toString('hex').should.not.equal(bufs[j].toString('hex'));
+    });
+
+  });
+
+  describe('getPseudoRandomBuffer', function() {
+
+    it('should generate 7 random bytes', function() {
+      var buf = Random.getPseudoRandomBuffer(7);
+      buf.length.should.equal(7);
+    });
+
+    it('should generate 8 random bytes', function() {
+      var buf = Random.getPseudoRandomBuffer(8);
+      buf.length.should.equal(8);
+    });
+
+    it('should generate 9 random bytes', function() {
+      var buf = Random.getPseudoRandomBuffer(9);
+      buf.length.should.equal(9);
+    });
+
+    it('should generate 90 random bytes', function() {
+      var buf = Random.getPseudoRandomBuffer(90);
+      buf.length.should.equal(90);
+    });
+
+    it('should generate two 8 byte buffers that are not equal', function() {
+      var buf1 = Random.getPseudoRandomBuffer(8);
+      var buf2 = Random.getPseudoRandomBuffer(8);
+      buf1.toString('hex').should.not.equal(buf2.toString('hex'));
+    });
+
+  });
+
+});