AACS (Advanced Access Content System) is a standard for content distribution and digital rights management, used as the access restriction scheme for HD DVD and Blu-ray disc to restrict access and copy.

AACS encrypts content under one or more title keys which are decrypted using a combination of a Media Key and the Volume ID of the media. The Media Key is encoded in a Media Key Block (MKB); and the Volume ID is a serial number stored on a pre-recorded disc with special hardware and cannot be duplicated on consumers' recordable media.

If you happened to have AACS encrypted Blu-rays, and want to copy them for collection or later private viewing, you need to use some software to decrypt AACS at first.

Passkey for Blu-ray, also known as Passkey Blu-ray Decrypter, is a powerful AACS decrypter which can decrypt MKB up to MKB v25. Once the MKB is decrypted, it provides the Media Key. The Media Key is combined with the Volume ID to produce the Volume Unique Key. The Volume Unique Key is used to decrypt the encrypted Title Keys, and the Title Key is used to decrypt the encrypted content. Till now, the AACS is successfully decrypted by Passkey.

The whole process of AACS decryption with Passkey is very simple. Just run Passkey for Blu-ray, then insert your AACS protected BD into BD drive, and Passkey will open (decrypt) it on-the-fly. Seconds later, everything will be done.

For more info about Passkey for Blu-ray, please go to:
http://www.passkeysoftware.com/passkey-for-blu-ray.html