BackupHDDVD is a small computer software utility program available in command line and GUI versions which aids in the decryption of commercial HD DVD discs protected by the Advanced Access Content System.

Users wanting to use the software to decrypt a protected disc's contents must obtain the appropriate keys separately, a task with which neither the original author nor his or her versions of BackupHDDVD assist.

The utility circumvents content protection by decrypting video files directly with AES, the underling cryptographic cipher used by AACS.

The cost of this immunity is that users are forced to rely on keys leaking from commercial player software to use BackupHDDVD with new discs.

[6][7] On December 18, 2006, a video which showed BackupHDDVD being used to decrypt and copy the film Full Metal Jacket to a hard drive was uploaded to YouTube.

The author elaborated in another forum post, claiming that keys could be obtained by exploiting the necessity for them to be held in memory to allow playback in player software.

On January 2, 2007, the author posted the 1.0 version of the BackupHDDVD utility, which included support for the decoding of discs using volume keys.

Further development of BackupHDDVD was being hosted on SourceForge until the site received a DMCA takedown notice alleging a violation in late February.

Through a standard AES library, it then decrypts each video file on the disc using the appropriate keys and writes the results to a location specified by the user.

Direct file decryption allows the utility's functionality to remain unaffected by device key revocation and its performance unencumbered with AACS overhead.

[3] Originally intended to be a proof of concept, BackupHDDVD is severely limited in its ability to produce fully functional copies of commercial discs.

The utility cannot process HD DVD navigation functionality which enables menus, chapters, secondary audio tracks and subtitles, so these features are inaccessible in copies created by BackupHDDVD.

[11] Under United States anti-circumvention law created by the Digital Millennium Copyright Act, BackupHDDVD may qualify as a device primarily intended to "circumvent a technological measure that effectively controls access to a [protected] work."