Initial Commit

iTechSharp/srcbc/tsp/TSPUtil.cs

@@ -0,0 +1,115 @@
+using System;
+using System.Collections;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.CryptoPro;
+using Org.BouncyCastle.Asn1.Nist;
+using Org.BouncyCastle.Asn1.Oiw;
+using Org.BouncyCastle.Asn1.Pkcs;
+using Org.BouncyCastle.Asn1.TeleTrust;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.X509;
+
+namespace Org.BouncyCastle.Tsp
+{
+	public class TspUtil
+	{
+		private static readonly IDictionary digestLengths = new Hashtable();
+		private static readonly IDictionary digestNames = new Hashtable();
+
+		static TspUtil()
+		{
+			digestLengths.Add(PkcsObjectIdentifiers.MD5.Id, 16);
+			digestLengths.Add(OiwObjectIdentifiers.IdSha1.Id, 20);
+			digestLengths.Add(NistObjectIdentifiers.IdSha224.Id, 28);
+			digestLengths.Add(NistObjectIdentifiers.IdSha256.Id, 32);
+			digestLengths.Add(NistObjectIdentifiers.IdSha384.Id, 48);
+			digestLengths.Add(NistObjectIdentifiers.IdSha512.Id, 64);
+
+			digestNames.Add(PkcsObjectIdentifiers.MD5.Id, "MD5");
+			digestNames.Add(OiwObjectIdentifiers.IdSha1.Id, "SHA1");
+			digestNames.Add(NistObjectIdentifiers.IdSha224.Id, "SHA224");
+			digestNames.Add(NistObjectIdentifiers.IdSha256.Id, "SHA256");
+			digestNames.Add(NistObjectIdentifiers.IdSha384.Id, "SHA384");
+			digestNames.Add(NistObjectIdentifiers.IdSha512.Id, "SHA512");
+			digestNames.Add(PkcsObjectIdentifiers.Sha1WithRsaEncryption.Id, "SHA1");
+			digestNames.Add(PkcsObjectIdentifiers.Sha224WithRsaEncryption.Id, "SHA224");
+			digestNames.Add(PkcsObjectIdentifiers.Sha256WithRsaEncryption.Id, "SHA256");
+			digestNames.Add(PkcsObjectIdentifiers.Sha384WithRsaEncryption.Id, "SHA384");
+			digestNames.Add(PkcsObjectIdentifiers.Sha512WithRsaEncryption.Id, "SHA512");
+			digestNames.Add(TeleTrusTObjectIdentifiers.RipeMD128.Id, "RIPEMD128");
+			digestNames.Add(TeleTrusTObjectIdentifiers.RipeMD160.Id, "RIPEMD160");
+			digestNames.Add(TeleTrusTObjectIdentifiers.RipeMD256.Id, "RIPEMD256");
+			digestNames.Add(CryptoProObjectIdentifiers.GostR3411.Id, "GOST3411");
+		}
+
+		/**
+		 * Validate the passed in certificate as being of the correct type to be used
+		 * for time stamping. To be valid it must have an ExtendedKeyUsage extension
+		 * which has a key purpose identifier of id-kp-timeStamping.
+		 *
+		 * @param cert the certificate of interest.
+		 * @throws TspValidationException if the certicate fails on one of the check points.
+		 */
+		public static void ValidateCertificate(
+			X509Certificate cert)
+		{
+			if (cert.Version != 3)
+				throw new ArgumentException("Certificate must have an ExtendedKeyUsage extension.");
+
+			Asn1OctetString ext = cert.GetExtensionValue(X509Extensions.ExtendedKeyUsage);
+			if (ext == null)
+				throw new TspValidationException("Certificate must have an ExtendedKeyUsage extension.");
+
+			if (!cert.GetCriticalExtensionOids().Contains(X509Extensions.ExtendedKeyUsage.Id))
+				throw new TspValidationException("Certificate must have an ExtendedKeyUsage extension marked as critical.");
+
+			try
+			{
+				ExtendedKeyUsage extKey = ExtendedKeyUsage.GetInstance(
+					Asn1Object.FromByteArray(ext.GetOctets()));
+
+				if (!extKey.HasKeyPurposeId(KeyPurposeID.IdKPTimeStamping) || extKey.Count != 1)
+					throw new TspValidationException("ExtendedKeyUsage not solely time stamping.");
+			}
+			catch (IOException)
+			{
+				throw new TspValidationException("cannot process ExtendedKeyUsage extension");
+			}
+		}
+
+		/// <summary>
+		/// Return the digest algorithm using one of the standard JCA string
+		/// representations rather than the algorithm identifier (if possible).
+		/// </summary>
+		internal static string GetDigestAlgName(
+			string digestAlgOID)
+		{
+			string digestName = (string) digestNames[digestAlgOID];
+
+			return digestName != null ? digestName : digestAlgOID;
+		}
+
+		internal static int GetDigestLength(
+			string digestAlgOID)
+		{
+			string digestName = GetDigestAlgName(digestAlgOID);
+
+			try
+			{
+				if (digestLengths.Contains(digestAlgOID))
+				{
+					return (int) digestLengths[digestAlgOID];
+				}
+
+				return DigestUtilities.GetDigest(digestName).GetDigestSize();
+			}
+			catch (SecurityUtilityException e)
+			{
+				throw new TspException("digest algorithm cannot be found.", e);
+			}
+		}
+	}
+}