1 files changed, 106 insertions, 0 deletions
diff --git a/Crypto/src/security/AgreementUtilities.cs b/Crypto/src/security/AgreementUtilities.cs
new file mode 100644
index 000000000..d74ec7368
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+++ b/Crypto/src/security/AgreementUtilities.cs
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+using System.Collections;
+using System.Globalization;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.X9;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Agreement;
+using Org.BouncyCastle.Crypto.Agreement.Kdf;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Security
+{
+	/// <remarks>
+	///  Utility class for creating IBasicAgreement objects from their names/Oids
+	/// </remarks>
+	public sealed class AgreementUtilities
+	{
+		private AgreementUtilities()
+		{
+		}
+
+		private static readonly IDictionary algorithms = Platform.CreateHashtable();
+        //private static readonly IDictionary oids = Platform.CreateHashtable();
+
+		static AgreementUtilities()
+		{
+			//algorithms[X9ObjectIdentifiers.DHSinglePassCofactorDHSha1KdfScheme.Id] = ?;
+			algorithms[X9ObjectIdentifiers.DHSinglePassStdDHSha1KdfScheme.Id] = "ECDHWITHSHA1KDF";
+			algorithms[X9ObjectIdentifiers.MqvSinglePassSha1KdfScheme.Id] = "ECMQVWITHSHA1KDF";
+		}
+
+		public static IBasicAgreement GetBasicAgreement(
+			DerObjectIdentifier oid)
+		{
+			return GetBasicAgreement(oid.Id);
+		}
+
+		public static IBasicAgreement GetBasicAgreement(
+			string algorithm)
+		{
+			string upper = algorithm.ToUpperInvariant();
+			string mechanism = (string) algorithms[upper];
+
+			if (mechanism == null)
+			{
+				mechanism = upper;
+			}
+
+			if (mechanism == "DH" || mechanism == "DIFFIEHELLMAN")
+				return new DHBasicAgreement();
+
+			if (mechanism == "ECDH")
+				return new ECDHBasicAgreement();
+
+			if (mechanism == "ECDHC")
+				return new ECDHCBasicAgreement();
+
+			if (mechanism == "ECMQV")
+				return new ECMqvBasicAgreement();
+
+			throw new SecurityUtilityException("Basic Agreement " + algorithm + " not recognised.");
+		}
+
+		public static IBasicAgreement GetBasicAgreementWithKdf(
+			DerObjectIdentifier oid,
+			string				wrapAlgorithm)
+		{
+			return GetBasicAgreementWithKdf(oid.Id, wrapAlgorithm);
+		}
+
+		public static IBasicAgreement GetBasicAgreementWithKdf(
+			string agreeAlgorithm,
+			string wrapAlgorithm)
+		{
+			string upper = agreeAlgorithm.ToUpperInvariant();
+			string mechanism = (string) algorithms[upper];
+
+			if (mechanism == null)
+			{
+				mechanism = upper;
+			}
+
+			// 'DHWITHSHA1KDF' retained for backward compatibility
+			if (mechanism == "DHWITHSHA1KDF" || mechanism == "ECDHWITHSHA1KDF")
+				return new ECDHWithKdfBasicAgreement(
+					wrapAlgorithm,
+					new ECDHKekGenerator(
+						new Sha1Digest()));
+
+			if (mechanism == "ECMQVWITHSHA1KDF")
+				return new ECMqvWithKdfBasicAgreement(
+					wrapAlgorithm,
+					new ECDHKekGenerator(
+						new Sha1Digest()));
+
+			throw new SecurityUtilityException("Basic Agreement (with KDF) " + agreeAlgorithm + " not recognised.");
+		}
+
+		public static string GetAlgorithmName(
+			DerObjectIdentifier oid)
+		{
+			return (string) algorithms[oid.Id];
+		}
+	}
+}