What Is CSS?
Content Scramble System (CSS), introduced around 1996 and was first compromised in 1999,
is a Digital Rights Management (DRM) and encryption system utilizing a 40-bit stream cipher algorithm and used on almost all commercial DVD-Video discs (most region 0 / all region DVDs are excepted).

Purpose of CSS
*CSS prevents byte-for-byte copies of DVDs from being playable since such copies do not include the keys of the protected discs.
*CSS provides a reason for manufacturers to make their devices compatible with CSS encrypted discs which cannot be played on noncompliant devices in principle.
 
Current Status of CSS
CSS has been replaced by newer DRM schemes such as Content Protection for Recordable Media (CPRM), or by Advanced Encryption Standard (AES) in the Advanced Access Content System (AACS) employed by Blu-ray and HD DVD, which have 56-bit and 128-bit key sizes respectively and provide a much higher level of security than the 40-bit key size of CSS.

Passkey Solution on CSS
Through above description, you now would understand that in principle if you want to play a CSS protected DVD on a noncompliant device, or you want to play a copy of a CSS encrypted disc, either won't work. However, Passkey can move CSS out of your disc just in seconds, and you can view it with any DVD player, and copy it using other software for a smooth playback.