@@ -158,11 +158,11 @@
 	if (length == 0)
 		return;
 
 	if (calculated)
 		@throw [OFHashAlreadyCalculatedException
-		    exceptionWithClass: isa
+		    exceptionWithClass: [self class]
 				  hash: self];
 
 	sha1_update(state, &count, buffer, buffer_, length);
 }