Editing Content Protection for Recordable Media

{{Redirect|CPRM|other uses|CPRM (disambiguation)}}

{{POV|date=October 2020}}
{{More citations needed|date=July 2021}}

'''Content Protection for Recordable Media and Pre-Recorded Media''' ('''CPRM / CPPM''') is a mechanism for restricting the copying, moving, and deletion of digital media on a host device, such as a personal computer, or other player. It is a form of [[digital rights management]] (DRM) developed by The [[4C Entity]], LLC (consisting of [[IBM]], [[Intel]], [[Panasonic|Matsushita]], and [[Toshiba]]).

The CPRM / CPPM specification defines a renewable [[cryptography|cryptographic]] method for restricting content when recorded on physical media. The currently implemented method utilizes the [[Cryptomeria cipher]] (C2) algorithm for symmetric encryption. The types of physical media supported include, but are not limited to, [[DVD recordable|recordable DVD]] media and [[flash memory]]. The most widespread use of CPRM is arguably in [[Secure Digital]] cards such as the [[SD-Audio]] standard.<ref>{{Cite web|url=https://www.sdcard.org/developers/overview/sd_apps/sd-audio/index.html|title = SD-Audio &#124; SD Association|date = 11 December 2020}}</ref> Note that the available 0.9 revision includes only the portions of the specification covering DVD media.

The CPRM / CPPM specification was designed to meet the requirements of [[intellectual property]] owners while balancing the implementation requirements of manufacturers. To accomplish these requirements, the system defined by the specification relies on [[public-key cryptography]]'s key management for interchangeable media, content encryption, and "media-based renewability."

The use of the CPRM specification and access to the <!--weasel word/newspeak: intellectual property and -->cryptographic materials required to implement it requires a license from [[4C Entity]], LLC. The license includes a facsimile <!-- what does this exactly mean in this context? --> key for the product which uses CPRM / CPPM technology.

A controversial proposal to add generic key exchange commands (that could be utilized by CPRM and other content restriction technologies) to [[parallel ATA|ATA]] specifications for removable hard drives was abandoned after outcry in 2001.<ref>
{{cite press release
| title = T13 Rejects Hard Drive Copy Prevention
| publisher = [[Electronic Frontier Foundation]]
| date = 2001-04-04
| url = http://w2.eff.org/IP/DRM/CPRM/20010404_eff_t13_pr.html
| accessdate = 2006-08-23
| archiveurl=https://web.archive.org/web/20150420140619/http://w2.eff.org/IP/DRM/CPRM/20010404_eff_t13_pr.html
| archive-date=April 20, 2015
}}</ref> CPRM is widely deployed in the popular [[Secure Digital]] card consumer-electronics flash memory format.{{cn|date=July 2021}}

== See also ==

* [[Burst cutting area]]
* [[DVD-Audio#Copy protection|DVD-Audio § Copy protection]]

== Notes and references ==
<references />

== External links ==

* [https://www.theregister.co.uk/2001/01/10/everything_you_ever_wanted/ 2001 The Register article on CPRM in ATA drives]

[[Category:Digital rights management standards]]
[[Category:Compact Disc and DVD copy protection]]