init commit

output/Libraries/BouncyCastle.Crypto/Org/BouncyCastle/Crypto/Tls/TlsMac.cs

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+using System;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Macs;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Tls;
+
+public class TlsMac
+{
+	protected readonly TlsContext context;
+
+	protected readonly byte[] secret;
+
+	protected readonly IMac mac;
+
+	protected readonly int digestBlockSize;
+
+	protected readonly int digestOverhead;
+
+	protected readonly int macLength;
+
+	public virtual byte[] MacSecret => secret;
+
+	public virtual int Size => macLength;
+
+	public TlsMac(TlsContext context, IDigest digest, byte[] key, int keyOff, int keyLen)
+	{
+		this.context = context;
+		KeyParameter keyParameter = new KeyParameter(key, keyOff, keyLen);
+		secret = Arrays.Clone(keyParameter.GetKey());
+		if (digest is LongDigest)
+		{
+			digestBlockSize = 128;
+			digestOverhead = 16;
+		}
+		else
+		{
+			digestBlockSize = 64;
+			digestOverhead = 8;
+		}
+		if (TlsUtilities.IsSsl(context))
+		{
+			mac = new Ssl3Mac(digest);
+			if (digest.GetDigestSize() == 20)
+			{
+				digestOverhead = 4;
+			}
+		}
+		else
+		{
+			mac = new HMac(digest);
+		}
+		mac.Init(keyParameter);
+		macLength = mac.GetMacSize();
+		if (context.SecurityParameters.truncatedHMac)
+		{
+			macLength = System.Math.Min(macLength, 10);
+		}
+	}
+
+	public virtual byte[] CalculateMac(long seqNo, byte type, byte[] message, int offset, int length)
+	{
+		ProtocolVersion serverVersion = context.ServerVersion;
+		bool isSsl = serverVersion.IsSsl;
+		byte[] array = new byte[isSsl ? 11 : 13];
+		TlsUtilities.WriteUint64(seqNo, array, 0);
+		TlsUtilities.WriteUint8(type, array, 8);
+		if (!isSsl)
+		{
+			TlsUtilities.WriteVersion(serverVersion, array, 9);
+		}
+		TlsUtilities.WriteUint16(length, array, array.Length - 2);
+		mac.BlockUpdate(array, 0, array.Length);
+		mac.BlockUpdate(message, offset, length);
+		return Truncate(MacUtilities.DoFinal(mac));
+	}
+
+	public virtual byte[] CalculateMacConstantTime(long seqNo, byte type, byte[] message, int offset, int length, int fullLength, byte[] dummyData)
+	{
+		byte[] result = CalculateMac(seqNo, type, message, offset, length);
+		int num = (TlsUtilities.IsSsl(context) ? 11 : 13);
+		int num2 = GetDigestBlockCount(num + fullLength) - GetDigestBlockCount(num + length);
+		while (--num2 >= 0)
+		{
+			mac.BlockUpdate(dummyData, 0, digestBlockSize);
+		}
+		mac.Update(dummyData[0]);
+		mac.Reset();
+		return result;
+	}
+
+	protected virtual int GetDigestBlockCount(int inputLength)
+	{
+		return (inputLength + digestOverhead) / digestBlockSize;
+	}
+
+	protected virtual byte[] Truncate(byte[] bs)
+	{
+		if (bs.Length <= macLength)
+		{
+			return bs;
+		}
+		return Arrays.CopyOf(bs, macLength);
+	}
+}