1 files changed, 253 insertions, 0 deletions
diff --git a/crypto/src/security/PublicKeyFactory.cs b/crypto/src/security/PublicKeyFactory.cs
new file mode 100644
index 000000000..c15e24a41
--- /dev/null
+++ b/crypto/src/security/PublicKeyFactory.cs
@@ -0,0 +1,253 @@
+using System;
+using System.Collections;
+using System.IO;
+using System.Text;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.CryptoPro;
+using Org.BouncyCastle.Asn1.Oiw;
+using Org.BouncyCastle.Asn1.Pkcs;
+using Org.BouncyCastle.Asn1.Sec;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Asn1.X9;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Generators;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Math.EC;
+
+namespace Org.BouncyCastle.Security
+{
+    public sealed class PublicKeyFactory
+    {
+        private PublicKeyFactory()
+        {
+        }
+
+		public static AsymmetricKeyParameter CreateKey(
+			byte[] keyInfoData)
+		{
+			return CreateKey(
+				SubjectPublicKeyInfo.GetInstance(
+					Asn1Object.FromByteArray(keyInfoData)));
+		}
+
+		public static AsymmetricKeyParameter CreateKey(
+			Stream inStr)
+		{
+			return CreateKey(
+				SubjectPublicKeyInfo.GetInstance(
+					Asn1Object.FromStream(inStr)));
+		}
+
+		public static AsymmetricKeyParameter CreateKey(
+			SubjectPublicKeyInfo keyInfo)
+        {
+            AlgorithmIdentifier algID = keyInfo.AlgorithmID;
+			DerObjectIdentifier algOid = algID.ObjectID;
+
+			// TODO See RSAUtil.isRsaOid in Java build
+			if (algOid.Equals(PkcsObjectIdentifiers.RsaEncryption)
+				|| algOid.Equals(X509ObjectIdentifiers.IdEARsa)
+				|| algOid.Equals(PkcsObjectIdentifiers.IdRsassaPss)
+				|| algOid.Equals(PkcsObjectIdentifiers.IdRsaesOaep))
+			{
+				RsaPublicKeyStructure pubKey = RsaPublicKeyStructure.GetInstance(
+					keyInfo.GetPublicKey());
+
+				return new RsaKeyParameters(false, pubKey.Modulus, pubKey.PublicExponent);
+			}
+			else if (algOid.Equals(X9ObjectIdentifiers.DHPublicNumber))
+			{
+				Asn1Sequence seq = Asn1Sequence.GetInstance(algID.Parameters.ToAsn1Object());
+
+				DHPublicKey dhPublicKey = DHPublicKey.GetInstance(keyInfo.GetPublicKey());
+
+				BigInteger y = dhPublicKey.Y.Value;
+
+				if (IsPkcsDHParam(seq))
+					return ReadPkcsDHParam(algOid, y, seq);
+
+				DHDomainParameters dhParams = DHDomainParameters.GetInstance(seq);
+
+				BigInteger p = dhParams.P.Value;
+				BigInteger g = dhParams.G.Value;
+				BigInteger q = dhParams.Q.Value;
+
+				BigInteger j = null;
+				if (dhParams.J != null)
+				{
+					j = dhParams.J.Value;
+				}
+
+				DHValidationParameters validation = null;
+				DHValidationParms dhValidationParms = dhParams.ValidationParms;
+				if (dhValidationParms != null)
+				{
+					byte[] seed = dhValidationParms.Seed.GetBytes();
+					BigInteger pgenCounter = dhValidationParms.PgenCounter.Value;
+
+					// TODO Check pgenCounter size?
+
+					validation = new DHValidationParameters(seed, pgenCounter.IntValue);
+				}
+
+				return new DHPublicKeyParameters(y, new DHParameters(p, g, q, j, validation));
+			}
+			else if (algOid.Equals(PkcsObjectIdentifiers.DhKeyAgreement))
+			{
+				Asn1Sequence seq = Asn1Sequence.GetInstance(algID.Parameters.ToAsn1Object());
+
+				DerInteger derY = (DerInteger) keyInfo.GetPublicKey();
+
+				return ReadPkcsDHParam(algOid, derY.Value, seq);
+			}
+			else if (algOid.Equals(OiwObjectIdentifiers.ElGamalAlgorithm))
+			{
+				ElGamalParameter para = new ElGamalParameter(
+					Asn1Sequence.GetInstance(algID.Parameters.ToAsn1Object()));
+				DerInteger derY = (DerInteger) keyInfo.GetPublicKey();
+
+				return new ElGamalPublicKeyParameters(
+					derY.Value,
+					new ElGamalParameters(para.P, para.G));
+			}
+			else if (algOid.Equals(X9ObjectIdentifiers.IdDsa)
+				|| algOid.Equals(OiwObjectIdentifiers.DsaWithSha1))
+			{
+				DerInteger derY = (DerInteger) keyInfo.GetPublicKey();
+				Asn1Encodable ae = algID.Parameters;
+
+				DsaParameters parameters = null;
+				if (ae != null)
+				{
+					DsaParameter para = DsaParameter.GetInstance(ae.ToAsn1Object());
+					parameters = new DsaParameters(para.P, para.Q, para.G);
+				}
+
+				return new DsaPublicKeyParameters(derY.Value, parameters);
+			}
+			else if (algOid.Equals(X9ObjectIdentifiers.IdECPublicKey))
+			{
+				X962Parameters para = new X962Parameters(algID.Parameters.ToAsn1Object());
+
+                X9ECParameters x9;
+				if (para.IsNamedCurve)
+				{
+					x9 = ECKeyPairGenerator.FindECCurveByOid((DerObjectIdentifier)para.Parameters);
+				}
+				else
+				{
+					x9 = new X9ECParameters((Asn1Sequence)para.Parameters);
+				}
+
+                Asn1OctetString key = new DerOctetString(keyInfo.PublicKeyData.GetBytes());
+                X9ECPoint derQ = new X9ECPoint(x9.Curve, key);
+                ECPoint q = derQ.Point;
+
+                if (para.IsNamedCurve)
+                {
+                    return new ECPublicKeyParameters("EC", q, (DerObjectIdentifier)para.Parameters);
+                }
+
+                ECDomainParameters dParams = new ECDomainParameters(x9.Curve, x9.G, x9.N, x9.H, x9.GetSeed());
+				return new ECPublicKeyParameters(q, dParams);
+			}
+			else if (algOid.Equals(CryptoProObjectIdentifiers.GostR3410x2001))
+			{
+				Gost3410PublicKeyAlgParameters gostParams = new Gost3410PublicKeyAlgParameters(
+					(Asn1Sequence) algID.Parameters);
+
+				Asn1OctetString key;
+				try
+				{
+					key = (Asn1OctetString) keyInfo.GetPublicKey();
+				}
+				catch (IOException)
+				{
+					throw new ArgumentException("invalid info structure in GOST3410 public key");
+				}
+
+				byte[] keyEnc = key.GetOctets();
+				byte[] x = new byte[32];
+				byte[] y = new byte[32];
+
+				for (int i = 0; i != y.Length; i++)
+				{
+					x[i] = keyEnc[32 - 1 - i];
+				}
+
+				for (int i = 0; i != x.Length; i++)
+				{
+					y[i] = keyEnc[64 - 1 - i];
+				}
+
+				ECDomainParameters ecP = ECGost3410NamedCurves.GetByOid(gostParams.PublicKeyParamSet);
+
+				if (ecP == null)
+					return null;
+
+				ECPoint q = ecP.Curve.CreatePoint(new BigInteger(1, x), new BigInteger(1, y), false);
+
+				return new ECPublicKeyParameters("ECGOST3410", q, gostParams.PublicKeyParamSet);
+			}
+			else if (algOid.Equals(CryptoProObjectIdentifiers.GostR3410x94))
+			{
+				Gost3410PublicKeyAlgParameters algParams = new Gost3410PublicKeyAlgParameters(
+					(Asn1Sequence) algID.Parameters);
+
+				DerOctetString derY;
+				try
+				{
+					derY = (DerOctetString) keyInfo.GetPublicKey();
+				}
+				catch (IOException)
+				{
+					throw new ArgumentException("invalid info structure in GOST3410 public key");
+				}
+
+				byte[] keyEnc = derY.GetOctets();
+				byte[] keyBytes = new byte[keyEnc.Length];
+
+				for (int i = 0; i != keyEnc.Length; i++)
+				{
+					keyBytes[i] = keyEnc[keyEnc.Length - 1 - i]; // was little endian
+				}
+
+				BigInteger y = new BigInteger(1, keyBytes);
+
+				return new Gost3410PublicKeyParameters(y, algParams.PublicKeyParamSet);
+			}
+            else
+            {
+                throw new SecurityUtilityException("algorithm identifier in key not recognised: " + algOid);
+            }
+        }
+
+		private static bool IsPkcsDHParam(Asn1Sequence seq)
+		{
+			if (seq.Count == 2)
+				return true;
+
+			if (seq.Count > 3)
+				return false;
+
+			DerInteger l = DerInteger.GetInstance(seq[2]);
+			DerInteger p = DerInteger.GetInstance(seq[0]);
+
+			return l.Value.CompareTo(BigInteger.ValueOf(p.Value.BitLength)) <= 0;
+		}
+
+		private static DHPublicKeyParameters ReadPkcsDHParam(DerObjectIdentifier algOid,
+			BigInteger y, Asn1Sequence seq)
+		{
+			DHParameter para = new DHParameter(seq);
+
+			BigInteger lVal = para.L;
+			int l = lVal == null ? 0 : lVal.IntValue;
+			DHParameters dhParams = new DHParameters(para.P, para.G, null, l);
+
+			return new DHPublicKeyParameters(y, dhParams, algOid);
+		}
+	}
+}