Abstract
AbstractOnline cipher is an important primitive in many cryptographic schemes, such as authenticated encryption schemes. Considering performance and security, the Hash-ECB-Hash (HEH) structure provides a potential way to construct parallelizable and CCA secure online cipher. In this paper, we start from the online cipher POE which is the only instantiation of Hash-ECB-Hash structure in the literature. However, the AXU property of hash function in the hash layer cannot guarantee the security of POE. Then we propose a new concept of online universal hash function (OUHF) for the hash layer and prove that the Hash-ECB-Hash structure is CCA secure, if the hash layer is online almost universal (OAU) hash function and the underlying block cipher is CCA secure. We also give several concrete constructions of OAU.KeywordsOnline cipherPOEHash-ECB-HashOnline universal hash function
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call