using Org.BouncyCastle.Crypto.Digests; namespace Org.BouncyCastle.Crypto.Kems.MLKem { internal abstract class Symmetric { internal sealed class ShakeSymmetric : Symmetric { private readonly ShakeDigest xof; private readonly Sha3Digest sha3Digest512; private readonly Sha3Digest sha3Digest256; private readonly ShakeDigest shakeDigest; internal ShakeSymmetric() : base(164) { xof = new ShakeDigest(128); shakeDigest = new ShakeDigest(256); sha3Digest256 = new Sha3Digest(256); sha3Digest512 = new Sha3Digest(512); } internal override void Hash_h(byte[] inBuf, int inOff, int inLen, byte[] outBuf, int outOff) { DoDigest(sha3Digest256, inBuf, inOff, inLen, outBuf, outOff); } internal override void Hash_g(byte[] input, byte[] output) { DoDigest(sha3Digest512, input, 0, input.Length, output, 0); } internal override void Kdf(byte[] input, byte[] output) { DoDigest(shakeDigest, input, 0, input.Length, output, 0); } internal override void Prf(byte[] seed, byte nonce, byte[] output) { shakeDigest.BlockUpdate(seed, 0, seed.Length); shakeDigest.Update(nonce); shakeDigest.OutputFinal(output, 0, output.Length); } internal override void XofAbsorb(byte[] seed, byte x, byte y) { byte[] array = new byte[2] { x, y }; xof.Reset(); xof.BlockUpdate(seed, 0, seed.Length); xof.BlockUpdate(array, 0, array.Length); } internal override void XofSqueezeBlocks(byte[] output, int outOffset, int outLen) { xof.Output(output, outOffset, outLen); } } internal readonly int XofBlockBytes; internal abstract void Hash_h(byte[] inBuf, int inOff, int inLen, byte[] outBuf, int outOff); internal abstract void Hash_g(byte[] input, byte[] output); internal abstract void Kdf(byte[] input, byte[] output); internal abstract void Prf(byte[] seed, byte nonce, byte[] output); internal abstract void XofAbsorb(byte[] seed, byte x, byte y); internal abstract void XofSqueezeBlocks(byte[] output, int outOffset, int outLen); internal Symmetric(int xofBlockBytes) { XofBlockBytes = xofBlockBytes; } internal static void DoDigest(IDigest digest, byte[] inBuf, int inOff, int inLen, byte[] outBuf, int outOff) { digest.BlockUpdate(inBuf, inOff, inLen); digest.DoFinal(outBuf, outOff); } } }