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Wireless broadcast is an effective approach to disseminate data to a number of users. To provide secure access to data in wireless broadcast services, symmetric 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 for access control in broadcast services. In this paper, we propose an efficient key management scheme (namely KTR) to key distribution with regarding to complex subscription options and user activities. KTR has the following advantages. First, it supports all subscription activities in wireless broadcast services. Second, in KTR, a user only needs to hold one set of keys for all subscribed programs, instead of separate sets of keys for each program. Third, KTR identifies the minimum set of keys that must be changed to ensure broadcast security and minimize the rekey cost. Our simulations show that KTR can save about 45% of communication overhead in the broadcast channel and about 50% of decryption cost for each user, compared with logical key hierarchy based approaches. Index Terms—Wireless broadcast, key management, access control, key hierarchy, secure group communication, key distribution |
