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 Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures, such as access control technologies, can restrict the use of proprietary hardware and copyrighted works. DRM ...

(DRM) developed by The 4C Entity, LLC (consisting of

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, and Delaware General Corporation Law, incorporated in Delaware. Intel designs, manufactures, and sells computer compo ...

, Matsushita, and

Toshiba is a Japanese multinational electronics company headquartered in Minato, Tokyo. Its diversified products and services include power, industrial and social infrastructure systems, elevators and escalators, electronic components, semiconductors ...

). The CPRM / CPPM specification defines a renewable

cryptographic Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or '' -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More gen ...

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, recordable DVD media and

flash memory Flash memory is an Integrated circuit, electronic Non-volatile memory, non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for t ...

. The most widespread use of CPRM is arguably in

Secure Digital Secure Digital (SD) is a proprietary, non-volatile, flash memory card format developed by the SD Association (SDA). Owing to their compact size, SD cards have been widely adopted in a variety of portable consumer electronics, including digi ...

cards such as the SD-Audio standard. 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 Intellectual property (IP) is a category of property that includes intangible creations of the human intellect. There are many types of intellectual property, and some countries recognize more than others. The best-known types are patents, co ...

owners while balancing the implementation requirements of manufacturers. To accomplish these requirements, the system defined by the specification relies on

public-key cryptography Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and a corresponding private key. Key pairs are generated with cryptographic alg ...

's key management for interchangeable media, content encryption, and "media-based renewability." The use of the CPRM specification and access to the cryptographic materials required to implement it requires a license from 4C Entity, LLC. The license includes a facsimile 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 ATA specifications for removable hard drives was abandoned after outcry in 2001. CPRM is widely deployed in the popular

card consumer-electronics flash memory format.{{cn, date=July 2021

Notes and references

External links

2001 The Register article on CPRM in ATA drives
Digital rights management standards Compact Disc and DVD copy protection

See also

Notes and references

External links