CNG, CryptoServiceProvider and Managed implementations of HashAlgorithm

Question

So I was wondering if there are any major differences between the various implementations of the hash algorithms, take the SHA series of algorithms for example. All of them

Answer 1

I did a quick and dirty comparison between CNG and managed on SHA512 which is the slowest of all SHA algorithms AFAIK using the code below.

    static void Main(string[] args)
    {
      int loops = 10000000;
      var data = Encoding.ASCII.GetBytes("123");

      var hashLoop = new Action((HashAlgorithm ha) =>
      {
        for (int i = 0; i < loops; i++)
          ha.ComputeHash(data);
      });

      var t1 = Task.Factory.StartNew(() =>
      {
        Time(hashLoop, new SHA512Managed());
      });
      var t2 = Task.Factory.StartNew(() =>
      {
        Time(hashLoop, new SHA512Cng());
      });

      Task.WaitAll(t1, t2);
      Console.WriteLine("Benchmark done!");
      Console.ReadKey();
    }
    static void Time(Action action, HashAlgorithm ha)
    {
      var sw = new Stopwatch();
      sw.Start();
      action(ha);
      sw.Stop();
      Console.WriteLine("{1} done in {0}ms", sw.ElapsedMilliseconds, ha.ToString());
    }

After several runs I found that the difference was that CNG was considerably faster than managed version of the algorithm with about 21.7% to 49.5%