There used to be an app called ReadThis!, which allowed you to store chunks of encrypted info in any of the text based apps (datebook, memopad, todo list, contacts). It relied on hackmaster so it doesn't work for the new palm devices.

Anyway, if I wanted to encrypt just a piece of a memo, It allowed me to just put a start tag and end tag around what I wanted to encrypt, and do a special key sequence and it would encrypt it, and everything outside of those tags was cleartext.

I like that better than the apps which are intended to put all your passwords and bank accounts in them. I want, for example, to keep my son's encrypted SSN together with the rest of the info about him that's cleartext (his phone number, IM name, etc).

Anyone have any suggestions?