Have you tried looking at the data file to see if there's any plaintext? The
question probably hasn't been answered because nobody here knows or cares
enough to go try and figure out. If you watch the NG for a while, you will
see that our rate of questions answered is very high.
I don't know what underlies the PPC version. On the XP side, it's MSISAM
which is, apparently, JET in drag. Newer versions of JET supposedly
actually do something to encrypt the data. I do not know how robust (cypher
strength) the encryption is. There have been password crack tools, however.
I also don't know whether these tools work well with strong passwords.
If you are really worried about this, I'd suggest you not use the PPC or use
it only in a reasonably RF-tight Faraday cage. There are other security
exposures besides loss of physical control of the device.