Libcrypt is the stadard Playstation protection used on many Playstation games. Some CD's are protected, others are not. The ones that are protected, need to be patched, so that a backup copy can be used, instead of the original game disc.
To find out if your game is protected, check out the list @
www.geocities.com/PSXCPLIST
-
OR-
Megagames
If you cannot find your game on the list, it must either:
a - be a very new game (in which you will have to wait until someone makes a patch for it)
b - be an old game, that is not protected, and therefore, will not need a patch.
You need to apply the patch to the CD image, created by CDRWIN, CloneCD (there are other programs, but these are the popular ones for good reason)
There are many tutorials, and posts that can give you the details on the actual patching. Just search for them.
I hope this has helped!