1 files changed, 59 insertions, 0 deletions
diff --git a/Crypto/src/x509/X509KeyUsage.cs b/Crypto/src/x509/X509KeyUsage.cs
new file mode 100644
index 000000000..e0a7b4939
--- /dev/null
+++ b/Crypto/src/x509/X509KeyUsage.cs
@@ -0,0 +1,59 @@
+using System;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.X509;
+
+namespace Org.BouncyCastle.X509
+{
+	/**
+	 * A holding class for constructing an X509 Key Usage extension.
+	 *
+	 * <pre>
+	 *    id-ce-keyUsage OBJECT IDENTIFIER ::=  { id-ce 15 }
+	 *
+	 *    KeyUsage ::= BIT STRING {
+	 *         digitalSignature        (0),
+	 *         nonRepudiation          (1),
+	 *         keyEncipherment         (2),
+	 *         dataEncipherment        (3),
+	 *         keyAgreement            (4),
+	 *         keyCertSign             (5),
+	 *         cRLSign                 (6),
+	 *         encipherOnly            (7),
+	 *         decipherOnly            (8) }
+	 * </pre>
+	 */
+	public class X509KeyUsage
+		: Asn1Encodable
+	{
+		public const int DigitalSignature = 1 << 7;
+		public const int NonRepudiation   = 1 << 6;
+		public const int KeyEncipherment  = 1 << 5;
+		public const int DataEncipherment = 1 << 4;
+		public const int KeyAgreement     = 1 << 3;
+		public const int KeyCertSign      = 1 << 2;
+		public const int CrlSign          = 1 << 1;
+		public const int EncipherOnly     = 1 << 0;
+		public const int DecipherOnly     = 1 << 15;
+
+		private readonly int usage;
+
+		/**
+		 * Basic constructor.
+		 *
+		 * @param usage - the bitwise OR of the Key Usage flags giving the
+		 * allowed uses for the key.
+		 * e.g. (X509KeyUsage.keyEncipherment | X509KeyUsage.dataEncipherment)
+		 */
+		public X509KeyUsage(
+			int usage)
+		{
+			this.usage = usage;
+		}
+
+		public override Asn1Object ToAsn1Object()
+		{
+			return new KeyUsage(usage);
+		}
+	}
+}