Griffin is a Conditional Access System developed by Nucleus Systems, Ltd. The SimulCrypt DVB CAS comprises of a PC/Linux system running the Griffin CAS Server software. For its use in set-top box receivers, it requires the use for a Smart Card. Griffin CAS Server provides ECM Generator (ECMG) and EMM Generator (EMMG) for every stream, as well as interface to the SMS.
Once the scrambled signal is received in the STB, the relevant ECMs and EMMs are sent to a Griffin smart-card. Depending on subscription and other criteria, CW and/or user data are returned to the STB, where the bulk of decryption for the entitled period is carried out by a hardware CSA descrambler.