1394 encryption inside TT-D2000 is controlled by TC81501F

Toshiba was sneaky and thought by mounting this chip on the underside of the tuner PCB they'd be able to avoid people noticing it. But in reality, this chip is irrelevant unless you're trying to physically attack DTCP. All it does is connect to the "undocumented" copy-protection port on the 1394 link layer controller, and does the encryption/decryption/authentication portion of DTCP. But guess what, once this decryption is done, the signal goes out IN THE CLEAR (lol) over the (documented) output port of 1394 controller. So much for clever design, Toshiba!

And now for a PR spin...
Toshiba has developed an LSI chip set "Conquest" for digital HDTV (High Definition TeleVision receivers). The LSI chip set conforms to specifications of the ARIB of Japan, and can be used not only for BS receivers, with data broadcasting service in Japan, but also for satellite broadcasting/CATV/and terrestrial broadcasting receivers in US (You wish, nobody wants your overpriced chipsets, wake the fuck up. Minimum cost of ISDB receiver is ~$300 USD, ATSC receivers can be had for 1/4 that price). The LSI chip set consists of an 8-PSK demodulator (TC90A54F), an MPEG audio/video decoder (TC90A55TB), a video/graphic processor (TC90A56TB), and an IEEE1394 copy protection processor (TC81501F). The LSIs, except TC81501F, utilize 0.25nm process technology and 2.5 V internal operating voltage. Using these technologies, power consumption has been reduced to 0.64 W for TC90A54F, 2.1 W for TC90A55TB, and 2.3 W for TC90A56TB. TC81501F prevents internal confidential data from external access by utilizing built-in EEPROM (Electrically Erasable and Programmable ROM) process. A later revision of this chipset, called "Conquest II", packed the video decoder and graphics processor into a single LSI, so that more or less one-chip STB solution is available.

TC8150F on TT-D2000 circuit board