A novel protocol for downloadable CAS

On the security of an novel protocol for downloadable CAS

“…• To prevent the replay attack or the man-in-the-middle attack, DCAS protocol is required mutual authentication between a secure chip (SC) in STB and a DCAS headend(DH) based on random challenges and trusted signatures [1].…”

“…When users moved to another residence, they not only had to change the local broadcaster but also replace the existing STB with new one. Therefore, a hardware-based CAS module was developed for updating of the CAS module instead of replacing the STB, and it could be removable [1]. However, this approach also has few drawbacks.…”

“…Second, the smartcard emits heat, which can cause fault operations of the STB. To solve these problems of existing CAS, a study of downloadable CAS (DCAS) was initiated in the next generation network architecture (NGNA) project supported by National Cable & Telecommunications Association (NCTA) [1]. The STB supporting DCAS has a special application-specific integrated circuit (ASIC) chip.…”

“…When users want to change from a particular broadcaster, they download the appropriate CAS software instead of replacing the STB of the CAS module. The standardization of DCAS was initiated by major multiple system operators (MSO) and manufacturers [1]. The most important component of DCAS is security.…”

“…Also, this protocol should optimize protocol messages in order to reduce hardware dependency and communication cost. In 2008, Jeong et al proposed a novel protocol for DCAS [1]. They claimed that their protocol provided secure downloading of CA software and it minimized the number of messages.…”