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

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+using System.Collections;
+using Org.BouncyCastle.Crypto.Agreement;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Tls;
+
+public class DefaultTlsDHVerifier : TlsDHVerifier
+{
+	public static readonly int DefaultMinimumPrimeBits;
+
+	protected static readonly IList DefaultGroups;
+
+	protected readonly IList mGroups;
+
+	protected readonly int mMinimumPrimeBits;
+
+	public virtual int MinimumPrimeBits => mMinimumPrimeBits;
+
+	private static void AddDefaultGroup(DHParameters dhParameters)
+	{
+		DefaultGroups.Add(dhParameters);
+	}
+
+	static DefaultTlsDHVerifier()
+	{
+		DefaultMinimumPrimeBits = 2048;
+		DefaultGroups = Platform.CreateArrayList();
+		AddDefaultGroup(DHStandardGroups.rfc7919_ffdhe2048);
+		AddDefaultGroup(DHStandardGroups.rfc7919_ffdhe3072);
+		AddDefaultGroup(DHStandardGroups.rfc7919_ffdhe4096);
+		AddDefaultGroup(DHStandardGroups.rfc7919_ffdhe6144);
+		AddDefaultGroup(DHStandardGroups.rfc7919_ffdhe8192);
+		AddDefaultGroup(DHStandardGroups.rfc3526_1536);
+		AddDefaultGroup(DHStandardGroups.rfc3526_2048);
+		AddDefaultGroup(DHStandardGroups.rfc3526_3072);
+		AddDefaultGroup(DHStandardGroups.rfc3526_4096);
+		AddDefaultGroup(DHStandardGroups.rfc3526_6144);
+		AddDefaultGroup(DHStandardGroups.rfc3526_8192);
+	}
+
+	public DefaultTlsDHVerifier()
+		: this(DefaultMinimumPrimeBits)
+	{
+	}
+
+	public DefaultTlsDHVerifier(int minimumPrimeBits)
+		: this(DefaultGroups, minimumPrimeBits)
+	{
+	}
+
+	public DefaultTlsDHVerifier(IList groups, int minimumPrimeBits)
+	{
+		mGroups = groups;
+		mMinimumPrimeBits = minimumPrimeBits;
+	}
+
+	public virtual bool Accept(DHParameters dhParameters)
+	{
+		if (CheckMinimumPrimeBits(dhParameters))
+		{
+			return CheckGroup(dhParameters);
+		}
+		return false;
+	}
+
+	protected virtual bool AreGroupsEqual(DHParameters a, DHParameters b)
+	{
+		if (a != b)
+		{
+			if (AreParametersEqual(a.P, b.P))
+			{
+				return AreParametersEqual(a.G, b.G);
+			}
+			return false;
+		}
+		return true;
+	}
+
+	protected virtual bool AreParametersEqual(BigInteger a, BigInteger b)
+	{
+		if (a != b)
+		{
+			return a.Equals(b);
+		}
+		return true;
+	}
+
+	protected virtual bool CheckGroup(DHParameters dhParameters)
+	{
+		foreach (DHParameters mGroup in mGroups)
+		{
+			if (AreGroupsEqual(dhParameters, mGroup))
+			{
+				return true;
+			}
+		}
+		return false;
+	}
+
+	protected virtual bool CheckMinimumPrimeBits(DHParameters dhParameters)
+	{
+		return dhParameters.P.BitLength >= MinimumPrimeBits;
+	}
+}