iCopyright (c), 2000 Trustees of Dartmouth College (Institute for Security Technology Studies). All rights Reserved. Supported under Award number 2000-DT-CX-K001 (S-1) from the Office of Justice Programs, National Institute of Justice, Department of Justice. Points of view in this document are those of the author(s) and do not necessarily represent the official position of the U.S. Department of Justice.