Add BouncyCastle PCL files v1.7.0

1 files changed, 70 insertions, 0 deletions

diff --git a/Crypto/src/crypto/tls/TlsDHUtilities.cs b/Crypto/src/crypto/tls/TlsDHUtilities.cs
new file mode 100644

index 000000000..733749ea1
--- /dev/null
+++ b/Crypto/src/crypto/tls/TlsDHUtilities.cs
@@ -0,0 +1,70 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Crypto.Agreement;
+using Org.BouncyCastle.Crypto.Generators;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Tls
+{
+	public abstract class TlsDHUtilities
+	{
+		public static byte[] CalculateDHBasicAgreement(DHPublicKeyParameters publicKey,
+			DHPrivateKeyParameters privateKey)
+		{
+			DHBasicAgreement dhAgree = new DHBasicAgreement();
+			dhAgree.Init(privateKey);
+			BigInteger agreement = dhAgree.CalculateAgreement(publicKey);
+			return BigIntegers.AsUnsignedByteArray(agreement);
+		}
+
+		public static AsymmetricCipherKeyPair GenerateDHKeyPair(SecureRandom random, DHParameters dhParams)
+		{
+			DHBasicKeyPairGenerator dhGen = new DHBasicKeyPairGenerator();
+			dhGen.Init(new DHKeyGenerationParameters(random, dhParams));
+			return dhGen.GenerateKeyPair();
+		}
+
+		public static DHPrivateKeyParameters GenerateEphemeralClientKeyExchange(SecureRandom random,
+			DHParameters dhParams, Stream output)
+		{
+			AsymmetricCipherKeyPair dhAgreeClientKeyPair = GenerateDHKeyPair(random, dhParams);
+			DHPrivateKeyParameters dhAgreeClientPrivateKey =
+				(DHPrivateKeyParameters)dhAgreeClientKeyPair.Private;
+
+			BigInteger Yc = ((DHPublicKeyParameters)dhAgreeClientKeyPair.Public).Y;
+			byte[] keData = BigIntegers.AsUnsignedByteArray(Yc);
+			TlsUtilities.WriteOpaque16(keData, output);
+
+			return dhAgreeClientPrivateKey;
+		}
+		
+		public static DHPublicKeyParameters ValidateDHPublicKey(DHPublicKeyParameters key)
+		{
+			BigInteger Y = key.Y;
+			DHParameters parameters = key.Parameters;
+			BigInteger p = parameters.P;
+			BigInteger g = parameters.G;
+
+			if (!p.IsProbablePrime(2))
+			{
+				throw new TlsFatalAlert(AlertDescription.illegal_parameter);
+			}
+			if (g.CompareTo(BigInteger.Two) < 0 || g.CompareTo(p.Subtract(BigInteger.Two)) > 0)
+			{
+				throw new TlsFatalAlert(AlertDescription.illegal_parameter);
+			}
+			if (Y.CompareTo(BigInteger.Two) < 0 || Y.CompareTo(p.Subtract(BigInteger.One)) > 0)
+			{
+				throw new TlsFatalAlert(AlertDescription.illegal_parameter);
+			}
+
+			// TODO See RFC 2631 for more discussion of Diffie-Hellman validation
+
+			return key;
+		}
+	}
+}
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