/// <summary>
/// Creates a new PassphrasePrng from a passphrase and salt,
/// and seeds it with the output of PBKDF2
/// </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 PBKDF2 (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
{
m_disposeEngine = DisposeEngine;
PBKDF2 pkcs = new PBKDF2(Digest, Iterations, false);
m_digest = Digest;
pkcs.Initialize(Salt, Passphrase);
m_rndData = new byte[m_digest.BlockSize];
pkcs.Generate(m_rndData);
}
catch (Exception e)
{
throw new Exception(e.Message);
}
m_position = 0;
}
private void PKCSTest(int Size, int Iterations, byte[] Salt, byte[] Key, byte[] Output)
{
byte[] outBytes = new byte[Size];
using (PBKDF2 gen = new PBKDF2(new SHA256(), Iterations))
{
gen.Initialize(Key, Salt);
gen.Generate(outBytes, 0, Size);
}
if (Evaluate.AreEqual(outBytes, Output) == false)
{
throw new Exception("PBKDF2: Values are not equal! Expected: " + HexConverter.ToString(Output) + " Received: " + HexConverter.ToString(outBytes));
}
using (PBKDF2 gen = new PBKDF2(new HMAC(new SHA256()), Iterations))
{
gen.Initialize(Key, Salt);
gen.Generate(outBytes, 0, Size);
}
if (Evaluate.AreEqual(outBytes, Output) == false)
{
throw new Exception("PBKDF2: Values are not equal! Expected: " + HexConverter.ToString(Output) + " Received: " + HexConverter.ToString(outBytes));
}
}
/// <summary>
/// Outputs expected values for the PBKDF2
/// </summary>
public string GetPBKDFVector(IDigest Engine, int Rounds = 100)
{
int keySize = Engine.BlockSize;
PBKDF2 pbk = new PBKDF2(Engine, Rounds);
byte[] salt = new byte[keySize];
byte[] output = new byte[1024];
for (int i = 0; i < salt.Length; i++)
{
salt[i] = (byte)i;
}
pbk.Initialize(salt);
pbk.Generate(output);
while (output.Length > 32)
{
output = Reduce(output);
}
return(HexConverter.ToString(output));
}