Construction of Revocable Broadcast Encryption Based on Witness Encryption

Witness encryption (WE) is a new type of encryption scheme without key generation. It can be used for construction of many other cryptosystems such as public key encryption, IBE, ABE, etc. A new WE application is presented, i.e., the construction of revocable broadcast encryption (BE) based on WE. The constructed BE scheme also supports a simple re-membership function, which is suitable for applications like pay-TV etc. In the construction, we also point out that the original security definition of WE is not strong enough. So we strengthen the original WE security definition and construct a WE scheme satisfying this new definition based on the original WE scheme, hard subset membership problem and random oracle model.