Security and privacy are important properties that have to be considered for the adoption of Vehicular Ad-hoc Networks (VANETs). Short-lived credentials, termed pseudonyms, are used to ensure message integrity and authentication while preserving vehicle (thus, their passengers') privacy. However, this introduces extra communication and computation overhead: pseudonyms have to be attached to the messages and signatures on pseudonyms and messages need to be verified before they can be accepted. In this poster, we are concerned with computation overhead for pseudonym validation. We preload vehicular On-Board Units (OBUs) with a Bloom Filter (BF) to facilitate pseudonym validation while traditional approach (i.e., signature verification on pseudonyms) can still be preserved as a fallback approach. We evaluate our scheme on automotive testbed with a preliminary implementation. Our scheme provides low processing delay for pseudonym validation at a cost of communication overhead for pre-downloading the BF.