1 files changed, 44 insertions, 0 deletions
diff --git a/Crypto/src/asn1/smime/SMIMEEncryptionKeyPreferenceAttribute.cs b/Crypto/src/asn1/smime/SMIMEEncryptionKeyPreferenceAttribute.cs
new file mode 100644
index 000000000..19c5fd78a
--- /dev/null
+++ b/Crypto/src/asn1/smime/SMIMEEncryptionKeyPreferenceAttribute.cs
@@ -0,0 +1,44 @@
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Org.BouncyCastle.Asn1.X509;
+
+namespace Org.BouncyCastle.Asn1.Smime
+{
+    /**
+     * The SmimeEncryptionKeyPreference object.
+     * <pre>
+     * SmimeEncryptionKeyPreference ::= CHOICE {
+     *     issuerAndSerialNumber   [0] IssuerAndSerialNumber,
+     *     receipentKeyId          [1] RecipientKeyIdentifier,
+     *     subjectAltKeyIdentifier [2] SubjectKeyIdentifier
+     * }
+     * </pre>
+     */
+    public class SmimeEncryptionKeyPreferenceAttribute
+        : AttributeX509
+    {
+        public SmimeEncryptionKeyPreferenceAttribute(
+            IssuerAndSerialNumber issAndSer)
+            : base(SmimeAttributes.EncrypKeyPref,
+                new DerSet(new DerTaggedObject(false, 0, issAndSer)))
+        {
+        }
+
+        public SmimeEncryptionKeyPreferenceAttribute(
+            RecipientKeyIdentifier rKeyID)
+            : base(SmimeAttributes.EncrypKeyPref,
+                new DerSet(new DerTaggedObject(false, 1, rKeyID)))
+        {
+        }
+
+        /**
+         * @param sKeyId the subjectKeyIdentifier value (normally the X.509 one)
+         */
+        public SmimeEncryptionKeyPreferenceAttribute(
+            Asn1OctetString sKeyID)
+            : base(SmimeAttributes.EncrypKeyPref,
+                new DerSet(new DerTaggedObject(false, 2, sKeyID)))
+        {
+        }
+    }
+}