The 4C Entity (which should be read out as "the four company entity") is a consortium formed by IBM, Intel, Matsushita and Toshiba to establish a common platform for digital rights management schemes. The activities center on the Cryptomeria cipher (also known as C2) which is a proprietary, patented cipher that needs to be licensed from the 4C Entity.
The 4C Entity has developed the Content Protection for Recordable Media (CPRM) and the Content Protection for Prerecorded Media (CPPM) schemes, sharing a lot of common features and therefore commonly known as CPPM/CPRM. The first successful implementation of the CPRM scheme is found in Secure Digital cards (SD cards). The SD card DRM scheme is however almost never used and often not supported by card reader hardware. All card manufacturers are required to implement it however. The CPPM scheme is adopted for DVD-Audio.
The 4C Entity also made a proposal for a sequel to the content-scrambling system (CSS) named CSS2, however after the first version was broken, the proposal was withdrawn.