//Number of default iterations. Somewhere between 50k and 500k is good to test
const int DefaultIterations = 100000;
const int NumBytes = 32;

//Initialize Generator
var Gen = new System.Security.Cryptography.Rfc2898DeriveBytes("SomePassword", 16, DefaultIterations);
//Measure Time
var DT = DateTime.UtcNow;
Gen.GetBytes(NumBytes);
var Runtime = DateTime.UtcNow.Subtract(DT).TotalMilliseconds;
//Calculate iterations for 1 second duration and round it to thousands.
var ProposedIterations = (int)(DefaultIterations / Runtime) * 1000;

//Write Statistics
Console.WriteLine("Initial Measurement:");
Console.WriteLine("Time (msec):        {0}", (int)Runtime);
Console.WriteLine("Iterations:         {0}", DefaultIterations);
Console.WriteLine("Proposed for 1 sec: {0}", ProposedIterations);

//Verify proposed iterations by doing it again
Console.WriteLine("Verifying...");
//Reinitialize Generator with proposed value for iterations
Gen = new System.Security.Cryptography.Rfc2898DeriveBytes("SomePassword", 16, ProposedIterations);
DT = DateTime.UtcNow;
Gen.GetBytes(NumBytes);
Runtime = DateTime.UtcNow.Subtract(DT).TotalMilliseconds;

//Write new Statistics
Console.WriteLine("Time (msec):        {0}", (int)Runtime);
Console.WriteLine("Iterations:         {0}", ProposedIterations);
Console.WriteLine("Proposed for 1 sec: {0}", (int)(ProposedIterations / Runtime) * 1000 /*round to 1000*/);

//If everything went alright,
//the new proposed value should almost match the first proposed value (5000 diff max).