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output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Signers/Ed25519phSigner.cs

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+using System;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math.EC.Rfc8032;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Signers;
+
+public class Ed25519phSigner : ISigner
+{
+	private readonly IDigest prehash = Ed25519.CreatePrehash();
+
+	private readonly byte[] context;
+
+	private bool forSigning;
+
+	private Ed25519PrivateKeyParameters privateKey;
+
+	private Ed25519PublicKeyParameters publicKey;
+
+	public virtual string AlgorithmName => "Ed25519ph";
+
+	public Ed25519phSigner(byte[] context)
+	{
+		this.context = Arrays.Clone(context);
+	}
+
+	public virtual void Init(bool forSigning, ICipherParameters parameters)
+	{
+		this.forSigning = forSigning;
+		if (forSigning)
+		{
+			privateKey = (Ed25519PrivateKeyParameters)parameters;
+			publicKey = privateKey.GeneratePublicKey();
+		}
+		else
+		{
+			privateKey = null;
+			publicKey = (Ed25519PublicKeyParameters)parameters;
+		}
+		Reset();
+	}
+
+	public virtual void Update(byte b)
+	{
+		prehash.Update(b);
+	}
+
+	public virtual void BlockUpdate(byte[] buf, int off, int len)
+	{
+		prehash.BlockUpdate(buf, off, len);
+	}
+
+	public virtual byte[] GenerateSignature()
+	{
+		if (!forSigning || privateKey == null)
+		{
+			throw new InvalidOperationException("Ed25519phSigner not initialised for signature generation.");
+		}
+		byte[] array = new byte[Ed25519.PrehashSize];
+		if (Ed25519.PrehashSize != prehash.DoFinal(array, 0))
+		{
+			throw new InvalidOperationException("Prehash digest failed");
+		}
+		byte[] array2 = new byte[Ed25519PrivateKeyParameters.SignatureSize];
+		privateKey.Sign(Ed25519.Algorithm.Ed25519ph, publicKey, context, array, 0, Ed25519.PrehashSize, array2, 0);
+		return array2;
+	}
+
+	public virtual bool VerifySignature(byte[] signature)
+	{
+		if (forSigning || publicKey == null)
+		{
+			throw new InvalidOperationException("Ed25519phSigner not initialised for verification");
+		}
+		byte[] encoded = publicKey.GetEncoded();
+		return Ed25519.VerifyPrehash(signature, 0, encoded, 0, context, prehash);
+	}
+
+	public void Reset()
+	{
+		prehash.Reset();
+	}
+}