Peter Gutmann, pgut001@cs.auckland.ac.nz http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html Last updated 12 June 2007 (but see the note below) Distributed under the Creative Commons license (see Appendix) In early August of this year I gave a talk at a security conference with a significantly more up-to-date and cleaned-up version of this material (the writeup here was originally written f