/// <summary>
/// Creates a new PassphrasePrng from a passphrase and salt,
/// and seeds it with the output of PKCS5
/// </summary>
///
/// <param name="Digest">Digest engine</param>
/// <param name="Passphrase">The passphrase</param>
/// <param name="Salt">The salt value</param>
/// <param name="Iterations">The number of transformation iterations performed by the digest with PKCS5 (default is 10,000)</param>
/// <param name="DisposeEngine">Dispose of digest engine when <see cref="Dispose()"/> on this class is called (default is true)</param>
///
/// <exception cref="CryptoRandomException">Thrown if a null Digest, Passphrase or Salt are used</exception>
public PBPRng(IDigest Digest, byte[] Passphrase, byte[] Salt, int Iterations = PKCS_ITERATIONS, bool DisposeEngine = true)
{
if (Digest == null)
throw new CryptoRandomException("PBPRng:Ctor", "Digest can not be null!", new ArgumentNullException());
if (Passphrase == null)
throw new CryptoRandomException("PBPRng:Ctor", "Passphrase can not be null!", new ArgumentNullException());
if (Salt == null)
throw new CryptoRandomException("PBPRng:Ctor", "Salt can not be null!", new ArgumentNullException());
try
{
_disposeEngine = DisposeEngine;
PKCS5 pkcs = new PKCS5(Digest, Iterations, false);
_digest = Digest;
pkcs.Initialize(Salt, Passphrase);
_rndData = new byte[_digest.BlockSize];
pkcs.Generate(_rndData);
}
catch (Exception e)
{
throw new Exception(e.Message);
}
_position = 0;
}
private void PKCSTest(int Size, int Iterations, byte[] Salt, byte[] Key, byte[] Output)
{
byte[] outBytes = new byte[Size];
using (PKCS5 gen = new PKCS5(new SHA256(), Iterations))
{
gen.Initialize(Salt, Key);
gen.Generate(outBytes, 0, Size);
}
if (Compare.AreEqual(outBytes, Output) == false)
throw new Exception("PKCS5: Values are not equal! Expected: " + HexConverter.ToString(Output) + " Received: " + HexConverter.ToString(outBytes));
using (PKCS5 gen = new PKCS5(new SHA256HMAC(), Iterations))
{
gen.Initialize(Salt, Key);
gen.Generate(outBytes, 0, Size);
}
if (Compare.AreEqual(outBytes, Output) == false)
throw new Exception("PKCS5: Values are not equal! Expected: " + HexConverter.ToString(Output) + " Received: " + HexConverter.ToString(outBytes));
}