BD+ update - StreetLock

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BD+ update - StreetLock

Post by mike admin » Wed Nov 16, 2016 5:30 pm

StreetLock is a new protection designed to lock the discs until a specific date. This protection is based on BD+ and is present on all discs with BD+ released after September 2016. In addition to AACS and BD+ the disc content is encrypted with a “Street Lock key”. Without the key released on a specific date (or after), it is cryptographically impossible to decrypt the BD+ FUT. (Technical info – data is encrypted with AES128 cipher using 88-bit key). The protection is currently enabled only for a small subset of players but eventually will cover all players.

On a first playback player tries to download the key from Internet and stores the key for later use. If the Internet connection is not available, player would require to enter the key by hand. Player will refuse to play the disc without working internet connection or manually entered key. While the keys are the same for all discs, the Java code on disc would require player to download a unique key for each disc. This is done to enable a truly evil "feature" - if the key is downloaded automatically (as opposed to entered manually), player also downloads a unique id (“cookie”) that is passed to BD+ code and is applied to watermark inserted into AV stream. The “cookie” size is about 80 bits. This “feature” is designed with plausible deniability in mind – the watermark data is designed to look like a cached speed-up data for a certain cryptographic operation and it is impossible to prove that it is used otherwise, yet it is a unique id downloaded by the player, assigned by a web server and later inserted into FUT data. As usual, ordinary users who just connect their player to the internet get "special treatment".

As of November 2016 MakeMKV is not affected – the player MakeMKV is emulating is not included into StreetLock subset.

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