1 files changed, 13 insertions, 5 deletions
diff --git a/crypto/src/asn1/DerBitString.cs b/crypto/src/asn1/DerBitString.cs
index 3f3697d99..9cf84db1e 100644
--- a/crypto/src/asn1/DerBitString.cs
+++ b/crypto/src/asn1/DerBitString.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Diagnostics;
+using System.IO;
 using System.Text;
 
 using Org.BouncyCastle.Math;
@@ -22,17 +23,24 @@ namespace Org.BouncyCastle.Asn1
 		{
 			if (obj == null || obj is DerBitString)
 			{
-				return (DerBitString) obj;
+				return (DerBitString)obj;
 			}
-            if (obj is byte[])
+            //else if (obj is Asn1BitStringParser)
+            else if (obj is IAsn1Convertible)
+            {
+                Asn1Object asn1Object = ((IAsn1Convertible)obj).ToAsn1Object();
+                if (asn1Object is DerBitString)
+                    return (DerBitString)asn1Object;
+            }
+            else if (obj is byte[])
             {
                 try
                 {
-                    return (DerBitString)FromByteArray((byte[])obj);
+                    return GetInstance(FromByteArray((byte[])obj));
                 }
-                catch (Exception e)
+                catch (IOException e)
                 {
-                    throw new ArgumentException("encoding error in GetInstance: " + e.ToString());
+                    throw new ArgumentException("failed to construct BIT STRING from byte[]: " + e.Message);
                 }
             }