Next, we check the integrity of the received tt(sha1sum) program. For this, we
use the monitor's tt(sha1sum) program:
        verb(
    LABEL \nCheck the client's sha1sum program
    LOCAL CHECK LOG = local/sha1 /usr/bin/sha1sum /root/tmp/sha1sum
        )
    The tt(LABEL) command writes the label to the report file just before
writing the tt(sha1sum) program's output.

    The tt(LOCAL) command checks the sha1sum of the program copied from the
client. The report is written on the file
tt(/root/stealth/client/local/sha1). If this fails, s() terminates, alerting
tt(admin@elsewhere) that the check failed. This is a serious event, as it
indicates that either the monitor's tt(sha1sum) is behaving unexpectedly or
that the client's tt(sha1sum) program has unexpectedly changed.

    The tt(sha1sum) program em(may) have changed due to a normal upgrade. If
so, tt(admin@elsewhere) will know this, and can (probably) ignore the
warning. The next time s() is run, the (now updated) SHA1 value is used, and
it again compares the obtained tt(SHA1) value to the one obtained for the
downloaded tt(sha1sum) program.

