init commit

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

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+using System;
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Signers;
+
+public class StandardDsaEncoding : IDsaEncoding
+{
+	public static readonly StandardDsaEncoding Instance = new StandardDsaEncoding();
+
+	public virtual BigInteger[] Decode(BigInteger n, byte[] encoding)
+	{
+		Asn1Sequence asn1Sequence = (Asn1Sequence)Asn1Object.FromByteArray(encoding);
+		if (asn1Sequence.Count == 2)
+		{
+			BigInteger bigInteger = DecodeValue(n, asn1Sequence, 0);
+			BigInteger bigInteger2 = DecodeValue(n, asn1Sequence, 1);
+			byte[] a = Encode(n, bigInteger, bigInteger2);
+			if (Arrays.AreEqual(a, encoding))
+			{
+				return new BigInteger[2] { bigInteger, bigInteger2 };
+			}
+		}
+		throw new ArgumentException("Malformed signature", "encoding");
+	}
+
+	public virtual byte[] Encode(BigInteger n, BigInteger r, BigInteger s)
+	{
+		return new DerSequence(EncodeValue(n, r), EncodeValue(n, s)).GetEncoded("DER");
+	}
+
+	protected virtual BigInteger CheckValue(BigInteger n, BigInteger x)
+	{
+		if (x.SignValue < 0 || (n != null && x.CompareTo(n) >= 0))
+		{
+			throw new ArgumentException("Value out of range", "x");
+		}
+		return x;
+	}
+
+	protected virtual BigInteger DecodeValue(BigInteger n, Asn1Sequence s, int pos)
+	{
+		return CheckValue(n, ((DerInteger)s[pos]).Value);
+	}
+
+	protected virtual DerInteger EncodeValue(BigInteger n, BigInteger x)
+	{
+		return new DerInteger(CheckValue(n, x));
+	}
+}