Betsi is Bellcore's Trusted Software Integrity System.

The purpose of Betsi is to allow users to verify that a
file or group of files has not changed since the 
certificate was obtained.

For more information on Betsi, including a copy of the
public key, send mail to certify@bellcore.com with
the subject: help.

Each directory in the skey distribution contains a
file Betsi.certificate. This certificate contains
the md5 digest of the files in the directory. The
certificate is signed with the public key of Betsi,
and the corresponding private key is carefully 
protected by Bellcore.

The help file (obtained by sending mail to certify) gives
instructions on obtaining a program for computing md5 
digests.