LmsUtilities
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Nist;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Security;
using System;
namespace Org.BouncyCastle.Pqc.Crypto.Lms
{
public static class LmsUtilities
{
internal class WrapperDigest : IDigest
{
private readonly IDigest m_digest;
private readonly int m_length;
public string AlgorithmName => m_digest.AlgorithmName;
internal WrapperDigest(IDigest digest, int length)
{
m_digest = digest;
m_length = length;
}
public void BlockUpdate(byte[] input, int inOff, int inLen)
{
m_digest.BlockUpdate(input, inOff, inLen);
}
public int DoFinal(byte[] output, int outOff)
{
byte[] array = new byte[m_digest.GetDigestSize()];
m_digest.DoFinal(array, 0);
Array.Copy(array, 0, output, outOff, m_length);
return m_length;
}
public int GetByteLength()
{
return m_digest.GetByteLength();
}
public int GetDigestSize()
{
return m_length;
}
public void Reset()
{
m_digest.Reset();
}
public void Update(byte input)
{
m_digest.Update(input);
}
}
public static void U32Str(int n, IDigest d)
{
d.Update((byte)(n >> 24));
d.Update((byte)(n >> 16));
d.Update((byte)(n >> 8));
d.Update((byte)n);
}
public static void U16Str(short n, IDigest d)
{
d.Update((byte)(n >> 8));
d.Update((byte)n);
}
public static void ByteArray(byte[] array, IDigest digest)
{
digest.BlockUpdate(array, 0, array.Length);
}
public static void ByteArray(byte[] array, int start, int len, IDigest digest)
{
digest.BlockUpdate(array, start, len);
}
public static int CalculateStrength(LmsParameters lmsParameters)
{
if (lmsParameters == null)
throw new ArgumentNullException("lmsParameters");
LMSigParameters lMSigParameters = lmsParameters.LMSigParameters;
return lMSigParameters.M << lMSigParameters.H;
}
internal static IDigest GetDigest(LMOtsParameters otsParameters)
{
return CreateDigest(otsParameters.DigestOid, otsParameters.N);
}
internal static IDigest GetDigest(LMSigParameters sigParameters)
{
return CreateDigest(sigParameters.DigestOid, sigParameters.M);
}
private static IDigest CreateDigest(DerObjectIdentifier oid, int length)
{
IDigest digest = CreateDigest(oid);
if (NistObjectIdentifiers.IdShake256Len.Equals(oid) || digest.GetDigestSize() != length)
return new WrapperDigest(digest, length);
return digest;
}
private static IDigest CreateDigest(DerObjectIdentifier oid)
{
if (NistObjectIdentifiers.IdSha256.Equals(oid))
return DigestUtilities.GetDigest(NistObjectIdentifiers.IdSha256);
if (NistObjectIdentifiers.IdShake256Len.Equals(oid))
return DigestUtilities.GetDigest(NistObjectIdentifiers.IdShake256);
throw new LmsException("unrecognized digest OID: " + oid?.ToString());
}
}
}