Data Encryption

Another ounce of prevention will keep any unauthorized user from hacking
directly into the data files of the device to try to take by force the
information contained within your PDA. The best method of making certain
that nobody can force information out of your device is to employ an
encryption algorithm that scrambles the internal device information
such that if anyone does gain directory access to your PDA (which is
possible through a number of directory-browsing Hot Sync programs),
the information would be useless without the proper encryption key.