/// <summary>
/// Generates 32 bit 2nd Key based on key option selected
/// </summary>
/// <param name="MasterSeed">Seed used to generate the key from m_2Key</param>
/// <param name="TransformSeed">Seed for key transformation</param>
/// <param name="NumRounds">Iteration count of transformation</param>
/// <returns></returns>
public byte[] Get2ndKey32(byte[] Hash, byte[] MasterSeed, byte[] TransformSeed)
{
byte[] GeneratedKey = new byte[32];
byte[] HashBuffer = new byte[32 + 32 + 32]; // MasterSeed + DualKey + FirstStreamHash
byte[] Key256Bits = null;
byte[] pKey32 = null;
try
{
Array.Copy(MasterSeed, 0, HashBuffer, 0, 32);
KdfParameters KdfParams = new AesKdf().GetDefaultParameters();
KdfParams.SetUInt64(AesKdf.ParamRounds, Key2Transformations);
KdfParams.SetByteArray(AesKdf.ParamSeed, TransformSeed);
var Key2nd = Get2ndKey();
if (Key2nd == null)
{
throw new SecurityException("Invalid 2nd Key");
}
ProtectedBinary pbinKey = Key2nd.GenerateKey32(KdfParams);
if (pbinKey == null)
{
throw new SecurityException("Invalid Key");
}
pKey32 = pbinKey.ReadData();
if ((pKey32 == null) || (pKey32.Length != 32))
{
throw new SecurityException("Invalid Key Data");
}
Array.Copy(pKey32, 0, HashBuffer, 32, 32);
Array.Copy(Hash, 0, HashBuffer, 64, 32);
SHA256Managed sha = new SHA256Managed();
Key256Bits = sha.ComputeHash(HashBuffer);
Array.Copy(Key256Bits, GeneratedKey, 32);
}
finally
{
MemUtil.ZeroByteArray(HashBuffer);
if (Key256Bits != null)
{
MemUtil.ZeroByteArray(Key256Bits);
}
if (pKey32 != null)
{
MemUtil.ZeroByteArray(pKey32);
}
}
return(GeneratedKey);
}
private byte[] GetKey()
{
byte[] ThreeDESKey = new byte[24];
MemoryStream ms = new MemoryStream();
ms.Write(m_MasterSeed, 0, 32);
KdfParameters kdf = new AesKdf().GetDefaultParameters();
kdf.SetUInt64(AesKdf.ParamRounds, m_NumRounds);
kdf.SetByteArray(AesKdf.ParamSeed, m_TransformSeed);
ProtectedBinary pbinKey = m_2Key.GenerateKey32(kdf);
if (pbinKey == null)
{
throw new SecurityException("Invalid Key");
}
byte[] pKey32 = pbinKey.ReadData();
if ((pKey32 == null) || (pKey32.Length != 32))
{
throw new SecurityException("Invalid Key Data");
}
ms.Write(pKey32, 0, 32);
byte[] sRandom = m_hash.Hash;
ms.Write(sRandom, 0, sRandom.Length);
SHA256Managed sha = new SHA256Managed();
byte[] Key256 = sha.ComputeHash(ms.ToArray());
Array.Copy(Key256, ThreeDESKey, ThreeDESKey.Length);
ms.Close();
Array.Clear(pKey32, 0, 32);
Array.Clear(Key256, 0, 32);
return(ThreeDESKey);
}