1 files changed, 2 insertions, 2 deletions
diff --git a/crypto/src/asn1/DerObjectIdentifier.cs b/crypto/src/asn1/DerObjectIdentifier.cs
index f9f6a79d6..6ac2b7e9e 100644
--- a/crypto/src/asn1/DerObjectIdentifier.cs
+++ b/crypto/src/asn1/DerObjectIdentifier.cs
@@ -26,7 +26,7 @@ namespace Org.BouncyCastle.Asn1
                 return (DerObjectIdentifier) obj;
             if (obj is byte[])
                 return FromOctetString((byte[])obj);
-            throw new ArgumentException("illegal object in GetInstance: " + obj.GetType().Name, "obj");
+            throw new ArgumentException("illegal object in GetInstance: " + Platform.GetTypeName(obj), "obj");
         }
 
         /**
@@ -83,7 +83,7 @@ namespace Org.BouncyCastle.Asn1
         public virtual bool On(DerObjectIdentifier stem)
         {
             string id = Id, stemId = stem.Id;
-            return id.Length > stemId.Length && id[stemId.Length] == '.' && id.StartsWith(stemId);
+            return id.Length > stemId.Length && id[stemId.Length] == '.' && Platform.StartsWith(id, stemId);
         }
 
         internal DerObjectIdentifier(byte[] bytes)