(Digital Transmission Copy Protection) DTCP Specification is to allow for protected transmission of copy-protected material between digital devices like PC's, DVD Players, and Digital TV's, five companies -- Hitachi, Intel, Matsushita (MEI), Sony and Toshiba have prepared the "5C" Digital Transmission Content Protection (DTCP) specification. The DTCP specification defines a cryptographic protocol for protecting audio/video entertainment content from illegal copying, intercepting and tampering as it traverses high performance digital buses, such as the IEEE 1394 standard. Only legitimate entertainment content delivered to a source device via another approved copy protection system (such as the DVD Content Scrambling System) will be protected by this copy protection system. The DTCP specification relies on strong cryptographic technologies to provide flexible and robust copy protection across digital buses.