PSPLock is a security software for PSP’s. It currently does not work on M33 firmwares.

Readme:

PSPLock now appears to be in EBOOT format. This is simply an easy installer that I’ve lovingly called
PEF (PSPLock Easy Flasher), all you have to do is run the program, select the options, and it does the hard work for you.

Increased security – Installed differently, which means you MUST read the README_PEF.txt

The ability to select characters (upper and lower case), punctuation, and numbers. Due to the above change, there is an easy scrolling option, pressing the triangle button will move you to the digits, the right should button to skip to upper case characters, and the left shoulder button to switch to lower case characters.

Faster load times, and although these are probably un-noticable, they are there.

Ability to select a “Button Switch”, this allows you to either force-crash the PSP if the buttons are not pressed upon bootup, or, if the buttons are pressed upon bootup, the PSP will switch manual/auto modes (so if you are on auto mode, it will switch to manual, and vise-versa). Of course, this option
can be disabled.

If the above “Button Switch” mode is activated, you will be asked to press 3 buttons, these will be the buttons used. If you only wish to have 1 of these buttons doing the job, press that button 3 times.

Increased compatibility with VSH plugins, almost all that I have tested work, with the exception of
CXMB.

http://forums.qj.net/f-psp-development-forum-11/t-release-psplock-v4-pef-v1-116029.html