1 files changed, 51 insertions, 0 deletions
diff --git a/crypto/src/cms/SignerId.cs b/crypto/src/cms/SignerId.cs
new file mode 100644
index 000000000..baac9369b
--- /dev/null
+++ b/crypto/src/cms/SignerId.cs
@@ -0,0 +1,51 @@
+using System;
+
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.X509.Store;
+
+namespace Org.BouncyCastle.Cms
+{
+    /**
+    * a basic index for a signer.
+    */
+    public class SignerID
+        : X509CertStoreSelector
+    {
+        public override int GetHashCode()
+        {
+            int code = Arrays.GetHashCode(this.SubjectKeyIdentifier);
+
+			BigInteger serialNumber = this.SerialNumber;
+			if (serialNumber != null)
+            {
+                code ^= serialNumber.GetHashCode();
+            }
+
+			X509Name issuer = this.Issuer;
+            if (issuer != null)
+            {
+                code ^= issuer.GetHashCode();
+            }
+
+			return code;
+        }
+
+        public override bool Equals(
+            object obj)
+        {
+			if (obj == this)
+				return false;
+
+			SignerID id = obj as SignerID;
+
+			if (id == null)
+				return false;
+
+			return Arrays.AreEqual(SubjectKeyIdentifier, id.SubjectKeyIdentifier)
+				&& Platform.Equals(SerialNumber, id.SerialNumber)
+				&& IssuersMatch(Issuer, id.Issuer);
+        }
+    }
+}