The security issue is always the most important concern of networked client-server application. On the putpose to build the secure group communication among of a group of client users and one server, in this paper, we will present a new password-based group key agreement protocol. Our protocol will meet simplicity, efficiency, and many desired security properties.
LU Rongxing CAO Zhenfu DONG Xiaolei SONG Chao SUN Congkai
Commitment scheme is a basic component of many cryptographic protocols, such as coin-tossing, identification schemes, zero-knowledge and multi-party computation. In order to prevent man-in-middle attacks, non-malleability is taken into account. Many forming works focus on designing non-malleable commitments schemes based on number theory assumptions. In this paper we give a general framework to construct non- interactive and non-malleable commitment scheme with respect to opening based on more general assumptions called q-one way group homomorphisms (q-OWGH). Our scheme is more general since many existing commitment schemes can be deduced from our scheme.
In this paper, we use the polynomial function and Chaum＇s RSA （Rivest, Shamir, Adleman） blind signature scheme to construct a secure anonymous internet electronic voting scheme. In our scheme, each vote does not need to be revealed in the tallying phase. The ballot number of each candidate gets is counted by computing the degrees of two polynomials＇ greatest common divisor. Our scheme does not require a special voting channel and communication can occur entirely over the current internet.
The improved RSA signature scheme can be strictly proved to be equivalent to the factoring problem. In the improved RSA signature scheme, when the public exponent e=1, the scheme becomes the improved Rabin signature. Such an improved Rabin signature scheme is reviewed and the techniques from the provable security is applied to analyze its security.
With recent advances of quantum computanon, new threats key cryptosystems. In order to build more secure bit commitment schemes, this paper gave a survey of the new coming braid-based cryptography and then brought forward the first braid-based bit commitment protocol. The security proof manifests that the proposed protocol is computationally binding and information-theoretically hiding. Furthermore, the proposed protocol is also invulnerable to currently known quantum attacks.
Peer-to-peer computing has recently started to gain significant acceptance, since it can greatly increase the performance and reliability of overall system. However, the security issue is still a major gating factor for its full adoption. In order to guarantee the security of data exchanged between two peers in Peer-to-Peer system, this paper comes up with an ID-based authenticated key agreement from bilinear pairings and uses BAN logic to prove the protocol’s security. Compared with other existing protocols, the proposed protocol seems more secure and efficient, since it adopts the static shared Diffie-Hellman key.
Remote user authentication is essential in distributed network environment to protect unauthorized access of a networked system. However, most of those existing remote user authentication schemes have not provided the user identity anonymity, while user anonymity is particularly important in some practical applications. Therefore, based on self-encryption mechanism, a new remote user authentication scheme was proposed. The scheme not only has no need of maintaining a password table at the remote server, but also can protect the user’s anonymity.
Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement （CB-AK） protocol with perfect forward secrecy is proposed. Our protocol makes use of pairings on elliptic curves. The protocol is described and its properties are discussed though comparison with Smart＇s protocol.
