using System;
using System.Text;

using NUnit.Framework;

using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Crypto.Signers;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Math.EC;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Utilities.Encoders;
using Org.BouncyCastle.Utilities.Test;

namespace Org.BouncyCastle.Crypto.Tests
{
	/**
	 *  ECGOST3410 tests are taken from GOST R 34.10-2001.
	 */
	[TestFixture]
	public class ECGost3410Test
		: SimpleTest
	{
		private static readonly byte[] hashmessage = Hex.Decode("3042453136414534424341374533364339313734453431443642453241453435");

		/**
		* ECGOST3410 over the field Fp<br/>
		*/
		BigInteger r = new BigInteger("29700980915817952874371204983938256990422752107994319651632687982059210933395");
		BigInteger s = new BigInteger("574973400270084654178925310019147038455227042649098563933718999175515839552");

		byte[] kData = new BigInteger("53854137677348463731403841147996619241504003434302020712960838528893196233395").ToByteArray();

		private readonly SecureRandom k;

		public ECGost3410Test()
		{
			k = FixedSecureRandom.From(kData);
		}

		private void ecGOST3410_TEST()
		{
			BigInteger mod_p = new BigInteger("57896044618658097711785492504343953926634992332820282019728792003956564821041"); //p

			FpCurve curve = new FpCurve(
				mod_p, // p
				new BigInteger("7"), // a
				new BigInteger("43308876546767276905765904595650931995942111794451039583252968842033849580414")); // b

			ECDomainParameters parameters = new ECDomainParameters(
				curve,
				new FpPoint(curve,
				new FpFieldElement(mod_p,new BigInteger("2")), // x
				new FpFieldElement(mod_p,new BigInteger("4018974056539037503335449422937059775635739389905545080690979365213431566280"))), // y
				new BigInteger("57896044618658097711785492504343953927082934583725450622380973592137631069619")); // q

			ECPrivateKeyParameters priKey = new ECPrivateKeyParameters(
				"ECGOST3410",
				new BigInteger("55441196065363246126355624130324183196576709222340016572108097750006097525544"), // d
				parameters);

			ParametersWithRandom param = new ParametersWithRandom(priKey, k);

			ECGost3410Signer ecgost3410 = new ECGost3410Signer();

			ecgost3410.Init(true, param);

			byte[] mVal = new BigInteger("20798893674476452017134061561508270130637142515379653289952617252661468872421").ToByteArray();
			byte[] message = new byte[mVal.Length];

			for (int i = 0; i != mVal.Length; i++)
			{
				message[i] = mVal[mVal.Length - 1 - i];
			}

			BigInteger[] sig = ecgost3410.GenerateSignature(message);

			if (!r.Equals(sig[0]))
			{
				Fail("r component wrong.", r, sig[0]);
			}

			if (!s.Equals(sig[1]))
			{
				Fail("s component wrong.", s, sig[1]);
			}

			// Verify the signature
			ECPublicKeyParameters pubKey = new ECPublicKeyParameters(
				"ECGOST3410",
				new FpPoint(curve,
				new FpFieldElement(mod_p, new BigInteger("57520216126176808443631405023338071176630104906313632182896741342206604859403")), // x
				new FpFieldElement(mod_p, new BigInteger("17614944419213781543809391949654080031942662045363639260709847859438286763994"))), // y
				parameters);

			ecgost3410.Init(false, pubKey);
			if (!ecgost3410.VerifySignature(message, sig[0], sig[1]))
			{
				Fail("verification fails");
			}
		}

		/**
		 * Test Sign and Verify with test parameters
		 * see: http://www.ietf.org/internet-drafts/draft-popov-cryptopro-cpalgs-01.txt
		 * gostR3410-2001-TestParamSet  P.46
		 */
		private void ecGOST3410_TestParam()
		{
			SecureRandom    random = new SecureRandom();

			BigInteger mod_p = new BigInteger("57896044618658097711785492504343953926634992332820282019728792003956564821041"); //p

			FpCurve curve = new FpCurve(
				mod_p, // p
				new BigInteger("7"), // a
				new BigInteger("43308876546767276905765904595650931995942111794451039583252968842033849580414")); // b

			ECDomainParameters parameters = new ECDomainParameters(
								   curve,
								   new FpPoint(curve,
								   new FpFieldElement(mod_p,new BigInteger("2")), // x
								   new FpFieldElement(mod_p,new BigInteger("4018974056539037503335449422937059775635739389905545080690979365213431566280"))), // y
								   new BigInteger("57896044618658097711785492504343953927082934583725450622380973592137631069619")); // q

			ECKeyPairGenerator          pGen = new ECKeyPairGenerator();
			ECKeyGenerationParameters   genParam = new ECKeyGenerationParameters(
				parameters,
				random);

			pGen.Init(genParam);

			AsymmetricCipherKeyPair  pair = pGen.GenerateKeyPair();

			ParametersWithRandom param = new ParametersWithRandom(pair.Private, random);

			ECGost3410Signer ecgost3410 = new ECGost3410Signer();

			ecgost3410.Init(true, param);

			//get hash message using the digest GOST3411.
			byte[] message = Encoding.ASCII.GetBytes("Message for sign");
			Gost3411Digest gost3411 = new Gost3411Digest();
			gost3411.BlockUpdate(message, 0, message.Length);
			byte[] hashmessage = new byte[gost3411.GetDigestSize()];
			gost3411.DoFinal(hashmessage, 0);

			BigInteger[] sig = ecgost3410.GenerateSignature(hashmessage);

			ecgost3410.Init(false, pair.Public);

			if (!ecgost3410.VerifySignature(hashmessage, sig[0], sig[1]))
			{
				Fail("signature fails");
			}
		}

		/**
		 * Test Sign and Verify with A parameters
		 * see: http://www.ietf.org/internet-drafts/draft-popov-cryptopro-cpalgs-01.txt
		 * gostR3410-2001-CryptoPro-A-ParamSet  P.47
		 */
		public void ecGOST3410_AParam()
		{
			SecureRandom    random = new SecureRandom();

			BigInteger mod_p = new BigInteger("115792089237316195423570985008687907853269984665640564039457584007913129639319"); //p

			FpCurve curve = new FpCurve(
				mod_p, // p
				new BigInteger("115792089237316195423570985008687907853269984665640564039457584007913129639316"), // a
				new BigInteger("166")); // b

			ECDomainParameters parameters = new ECDomainParameters(
				curve,
				new FpPoint(curve,
				new FpFieldElement(mod_p, new BigInteger("1")), // x
				new FpFieldElement(mod_p, new BigInteger("64033881142927202683649881450433473985931760268884941288852745803908878638612"))), // y
				new BigInteger("115792089237316195423570985008687907853073762908499243225378155805079068850323")); // q

			ECKeyPairGenerator pGen = new ECKeyPairGenerator("ECGOST3410");
			ECKeyGenerationParameters genParam = new ECKeyGenerationParameters(
				parameters,
				random);

			pGen.Init(genParam);

			AsymmetricCipherKeyPair  pair = pGen.GenerateKeyPair();

			ParametersWithRandom param = new ParametersWithRandom(pair.Private, random);

			ECGost3410Signer ecgost3410 = new ECGost3410Signer();

			ecgost3410.Init(true, param);

			BigInteger[] sig = ecgost3410.GenerateSignature(hashmessage);

			ecgost3410.Init(false, pair.Public);

			if (!ecgost3410.VerifySignature(hashmessage, sig[0], sig[1]))
			{
				Fail("signature fails");
			}
		}

		/**
		 * Test Sign and Verify with B parameters
		 * see: http://www.ietf.org/internet-drafts/draft-popov-cryptopro-cpalgs-01.txt
		 * gostR3410-2001-CryptoPro-B-ParamSet  P.47-48
		 */
		private void ecGOST3410_BParam()
		{
			SecureRandom random = new SecureRandom();

			BigInteger mod_p = new BigInteger("57896044618658097711785492504343953926634992332820282019728792003956564823193"); //p

			FpCurve curve = new FpCurve(
				mod_p, // p
				new BigInteger("57896044618658097711785492504343953926634992332820282019728792003956564823190"), // a
				new BigInteger("28091019353058090096996979000309560759124368558014865957655842872397301267595")); // b

			ECDomainParameters parameters = new ECDomainParameters(
				curve,
				new FpPoint(curve,
				new FpFieldElement(mod_p,new BigInteger("1")), // x
				new FpFieldElement(mod_p,new BigInteger("28792665814854611296992347458380284135028636778229113005756334730996303888124"))), // y
				new BigInteger("57896044618658097711785492504343953927102133160255826820068844496087732066703")); // q

			ECKeyPairGenerator pGen = new ECKeyPairGenerator("ECGOST3410");
			ECKeyGenerationParameters genParam = new ECKeyGenerationParameters(
				parameters,
				random);

			pGen.Init(genParam);

			AsymmetricCipherKeyPair pair = pGen.GenerateKeyPair();

			ParametersWithRandom param = new ParametersWithRandom(pair.Private, random);

			ECGost3410Signer ecgost3410 = new ECGost3410Signer();

			ecgost3410.Init(true, param);

			BigInteger[] sig = ecgost3410.GenerateSignature(hashmessage);

			ecgost3410.Init(false, pair.Public);

			if (!ecgost3410.VerifySignature(hashmessage, sig[0], sig[1]))
			{
				Fail("signature fails");
			}
		}

		/**
		 * Test Sign and Verify with C parameters
		 * see: http://www.ietf.org/internet-drafts/draft-popov-cryptopro-cpalgs-01.txt
		 * gostR3410-2001-CryptoPro-C-ParamSet  P.48
		 */
		private void ecGOST3410_CParam()
		{
			SecureRandom random = new SecureRandom();

			BigInteger mod_p = new BigInteger("70390085352083305199547718019018437841079516630045180471284346843705633502619"); //p

			FpCurve curve = new FpCurve(
				mod_p, // p
				new BigInteger("70390085352083305199547718019018437841079516630045180471284346843705633502616"), // a
				new BigInteger("32858")); // b

			ECDomainParameters parameters = new ECDomainParameters(
				curve,
				new FpPoint(curve,
				new FpFieldElement(mod_p,new BigInteger("0")), // x
				new FpFieldElement(mod_p,new BigInteger("29818893917731240733471273240314769927240550812383695689146495261604565990247"))), // y
				new BigInteger("70390085352083305199547718019018437840920882647164081035322601458352298396601")); // q

			ECKeyPairGenerator pGen = new ECKeyPairGenerator("ECGOST3410");
			ECKeyGenerationParameters genParam = new ECKeyGenerationParameters(
				parameters,
				random);

			pGen.Init(genParam);

			AsymmetricCipherKeyPair pair = pGen.GenerateKeyPair();

			ParametersWithRandom param = new ParametersWithRandom(pair.Private, random);

			ECGost3410Signer ecgost3410 = new ECGost3410Signer();

			ecgost3410.Init(true, param);

			BigInteger[] sig = ecgost3410.GenerateSignature(hashmessage);

			ecgost3410.Init(false, pair.Public);

			if (!ecgost3410.VerifySignature(hashmessage, sig[0], sig[1]))
			{
				Fail("signature fails");
			}
		}

		public override string Name
		{
			get { return "ECGOST3410"; }
		}

		public override void PerformTest()
		{
			ecGOST3410_TEST();
			ecGOST3410_TestParam();
			ecGOST3410_AParam();
			ecGOST3410_BParam();
			ecGOST3410_CParam();
		}

		public static void Main(
			string[] args)
		{
			ECGost3410Test test = new ECGost3410Test();
			ITestResult result = test.Perform();

			Console.WriteLine(result);
		}

		[Test]
		public void TestFunction()
		{
			string resultText = Perform().ToString();

			Assert.AreEqual(Name + ": Okay", resultText);
		}
	}
}
