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//
// Mono.Security.Cryptography.RNGCryptoServiceProvider
//
// Authors:
// Sebastien Pouliot (spouliot@motus.com)
//
// Copyright (C) 2003 Motus Technologies Inc. (http://www.motus.com)
//
using System;
using System.Security.Cryptography;
using System.Text;
namespace Mono.Security.Cryptography {
public class RNGCryptoServiceProvider : RandomNumberGenerator {
private CapiRandomNumberGenerator rng;
private byte[] seed;
public RNGCryptoServiceProvider ()
{
rng = new CapiRandomNumberGenerator ();
seed = null;
}
public RNGCryptoServiceProvider (byte[] rgb)
{
rng = new CapiRandomNumberGenerator ();
seed = rgb;
}
public RNGCryptoServiceProvider (CspParameters cspParams)
{
rng = new CapiRandomNumberGenerator (cspParams);
seed = null;
}
public RNGCryptoServiceProvider (string str)
{
rng = new CapiRandomNumberGenerator ();
seed = Encoding.Default.GetBytes (str);
}
~RNGCryptoServiceProvider ()
{
// zeroize seed
if (seed != null)
Array.Clear (seed, 0, seed.Length);
// release unmanaged resources
rng.Dispose ();
}
public override void GetBytes (byte[] data)
{
if (data == null)
throw new ArgumentNullException ("data");
// send the seed
if (seed != null)
rng.GenRandom (seed);
// note: by doing this seed is modified each time
rng.GenRandom (data);
// generate random
if (!rng.Result)
throw new CryptographicException (rng.Error);
}
public override void GetNonZeroBytes (byte[] data)
{
byte[] random = new byte [data.Length * 2];
int i = 0;
// one pass should be enough but hey this is random ;-)
while (i < data.Length) {
GetBytes (random);
for (int j=0; j < random.Length; j++) {
if (i == data.Length)
break;
if (random [j] != 0)
data [i++] = random [j];
}
}
}
}
}
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