NIST is developing Computer Forensic Reference Data Sets (CFReDS) for digital evidence. These reference data sets (CFReDS) provide to an investigator documented sets of simulated digital evidence for examination. Since CFReDS would have documented contents, such as target search strings seeded in known locations of CFReDS, investigators could compare the results of searches for the target strings with the known placement of the strings. Investigators could use CFReDS in several ways including validating the software tools used in their investigations, equipment check out, training investigators, and proficiency testing of investigators as part of laboratory accreditation. The CFReDS site is a repository of images. Some images are produced by NIST, often from the CFTT (tool testing) project, and some are contributed by other organizations. National Institute of Justice funded this work in part through an interagency agreement with the NIST Office of Law Enforcement Standards.