Yesterday, a New York Times article cited a posting by several graduate students at Berkeley about the insecurity of the Internet. We found the sci.crypt posting very interesting and relevant because we spent a good portion of the summer working to address the same problem. Namely, detection of the malicious (or other) modification of an executable in transit over an untrusted network. In particular, we believe that our system could be used to solve the NFS problem mentioned in the posting from Berkeley. Our paper can be accessed at ftp://thumper.bellcore.com/pub/rubin/stretch.ps Avi Rubin <rubin@bellcore.com> Trent Jaeger <jaegert@eecs.umich.edu>