Tasker + Password Lock plugin - Tasker | Google Groups
It should help you with a plugin that allows you to switch between the types of locks.
Setup the type of lock you want in settings - Location & security - set up screen lock
In tasker: The context for what you want would be the same as your other texting profiles only searching for another secret word.
the task would be as follows
+ - display - keyguard on
You could also set another profile to search for another word to remotely turn it off
+ - display - keyguard off
The link to the password locker plug in is bad in the link above. Use this: http://www.appbrain.com/app/locale-p...PasswordPlugin