eKTR: an Efficient Key Management Scheme in Wireless Data Broadcast Services

Wireless broadcast is an effective approach to disseminate data to a number of users. To provide secure access to the broadcast data, key-based encryption is used to ensure that only users who own the valid keys can decrypt the data. Regarding various subscriptions, an efficient key management to distribute and change keys is in great demand in the broadcast system. In this paper, we propose an efficient key management scheme, eKTR, to address this issue. eKTR lets multiple programs share a single key tree so that the users subscribing these programs can hold less keys. In eKTR, we also propose an approach to further reduce rekey cost by identifying the minimum set of keys that must be changed to ensure broadcast security. Our simulations show that eKTR can save about 45% of communication overhead in the broadcast channel and about 50% of decryption cost for each user, compared with the traditional logical key hierarchy based approach.