Practical Applications of Bloom Filters to the NIST RDS and Hard Drive Triage

Abstract

Much effort has been expended in recent years to create large sets of hash codes from known files. Distributing these sets has become more difficult as these sets grow larger. Meanwhile the value of these sets for eliminating the need to analyze "known goods'' has decreased as hard drives have dramatically increased in storage capacity. This paper evaluates the use of bloom filters (BFs) to distribute the National Software Reference Library's (NSRL) Reference Data Set (RDS)version 2.19, with 13 million SHA-1 hashes. We present an open source reference BF implementation and validate it against a large collection of disk images. We discuss the tuning of the filters, evaluate discuss how they can be used to enable new forensic functionality, and present a novel attack against bloom filters.