This paper presents a deniable authenticated key agreement protocol. This protocol can provide an authenticated session key while the sender and the receiver can deny their involvement in such a protocol if the protocol is executed successfully. Then both can deny their transmitted messages protected by the authenticated session key. If this protocol fails, no authenticated session key can be established and no protected messages can be transmitted. The protocol can be proved secure against key compromise impersonation attack. The protocol employs a new method to isolate a session key from confirmation keys.
TIAN Haibo1,2, CHEN Xiaofeng1,2, ZHANG Fangguo1,2, WEI Baodian1,2 1. School of Information Science and Technology, Sun Yat-Sen University, Guangzhou 510006, Guangdong, China
IEEE 802.16e, as an amendment and corrigendum to the IEEE 802.16-2004, published on 28 February 2006, and intended to update and expand IEEE 802.16-2004 to allow for mobile subscriber stations. This paper summarizes the key management protocol belonging to security part of the IEEE 802.16e, which includes security negotiation, authorization, key derivation, handshake, and key transportation. While these building blocks are well designed, we point out some unwelcome features for these building blocks. We also give out suggestions to diminish the proposed problems.
Combined with two chaotic maps, a novel alternate structure is applied to image cryptosystem. In proposed algorithm, a general cat-map is used for permutation and diffusion, as well as the OCML （one-way coupled map lattice）, which is applied for substitution. These two methods are operated alternately in every round of encryption process, where two subkeys employed in different chaotic maps are generated through the masterkey spreading. Decryption has the same structure with the encryption algorithm, but the masterkey in each round should be reversely ordered in decryption. The cryptanalysis shows that the proposed algorithm bears good immunities to many forms of attacks. Moreover, the algorithm features high execution speed and compact program, which is suitable for various software and hardware applications.
Universal designated verifier signature schemes allows a signature holder to designate the signature to a desire designated verifier, in such a way that only designated verifier can verify this signature, but is unable to convince anyone else of this fact. The previous constructions of universal designated verifier signature rely on the underlying public key infrastructure, that needs both signers and verifiers to verify the authenticity of the public keys, and hence, the certificates are required. This article presents the first model and construction of the certificateless universal designated verifier signature scheme, in which the certificates are not needed. The proposed scheme satisfies all the requirements of the universal designated verifier signature in the certificateless system. Security proofs are provided for the scheme based on the random oracle model, assuming that the Bilinear diffie-hellman （BDH） problem is hard to solve.
