Wen Qiaoyan

Cryptanalysis of the arbitrated quantum signature protocols

As a new model for signing quantum messages, arbitrated quantum signature (AQS) has recently received a lot of attention. In this paper we study the cryptanalysis of previous AQS protocols from the aspects of forgery and disavowal. We show that in these protocols the receiver, Bob, can realize existential forgery of the senders signature under known message attack. Bob can even achieve universal forgery when the protocols are used to sign a classical message. Furthermore, the sender, Alice, can successfully disavow any of her signatures by simple attack. The attack strategies are described in detail and some discussions about the potential improvements of the protocols are given. Finally we also present several interesting topics on AQS protocols that can be studied in future.

A DNS Based Anti-phishing Approach

Most of the phishing and pharming attacks are directed at the payment and financial services, with the purpose to steal online bank users’ card number and password. This paper presents the design and implementation of a DNS based anti-phishing approach, which can be used to protect the card number and the password of the online bank users effectively, and prevent phishers and pharmers from stealing such information. First, the bank name, its DNS server’s IP address, and the card number range will be stored in the database. If the Phishing Detecting Device detects that a bank card number is being sent to a suspicious website, the device will send an inverse DNS query to the DNS server of the related bank. By verifying whether the suspicious website is with in the domain of the bank, it can determine whether the website is a phishing website.

Probabilistic teleportation of a non-symmetric three-particle state

This paper proposes a scheme for teleporting a kind of essential three-particle non-symmetric entangled state, which is much more valuable than a GHZ and W state for some applications in quantum information processing. In comparison with previous proposal of teleportation, the resources of entangled states as quantum channel and the number of classical messages required by our scheme can be cut down. Moreover, it is shown that there exists a class of transformations which ensure the success of this scheme, because the two-particle transformation performed by the receiver in the course of teleportation may be a generic two-particle operation instead of a control-NOT (CNOT) operation. In addition, all kinds of transformations performed by sender and receiver are given in detail.

Secure Pairwise Key Establishment for Key Predistribution in Wireless Sensor Networks

Key establishment has been a challenging problem in wireless sensor networks. With the increasing of the sensor network applications, many key predistribution schemes are proposed. In most key predistribution schemes, sensors are loaded with preassigned keys. Sensor nodes discover common keys to establish secure connection with neighboring nodes. Nodes that are not directly connected use intermediate nodes which form a path to establish common keys. However, these schemes are vulnerable to stop forwarding attacks and intermediate nodes along the path may reveal the key. This paper presents a secret sharing based multi-path key establishment mechanism to counter these attacks. The proposed mechanism can be combined with other predistribution schemes. The analysis to our scheme indicates that it achieves better security performance.

Three-Tangle for High-Rank Mixed States

A family of rank-n (n = 5,6,7,8) three-qubit mixed states are constructed. The explicit expressions for the three-tangle and optimal decompositions for all these states are given. The CKW relations for these states are also discussed.

Improving the propagation characteristics of Boolean function and cheating immune secret sharing

An effective method for transforming Boolean functions that do not satisfy the propagation characteristics into ones that satisfy the criterion. Zhang X. M. and Pieprzyk J., (2001) constructed cheating immune secret sharing only for even integer. Such a method can be used to construct cheating immune secret sharing with high nonlinearity for any integer.

Two fast algorithms for computing point scalar multiplications on elliptic curves

The key operation in Elliptic Curve Cryptosystems(ECC) is point scalar multiplication. Making use of Frobenius endomorphism, Müller and Smart proposed two efficient algorithms for point scalar multiplications over even or odd finite fields respectively. This paper reduces the corresponding multiplier by modulo τk−1+…+τ+1 and improves the above algorithms. Implementation of our Algorithm 1 in Maple for a given elliptic curve shows that it is at least as twice fast as binary method. By setting up a precomputation table, Algorithm 2, an improved version of Algorithm 1, is proposed. Since the time for the precomputation table can be considered free, Algorithm 2 is about (3/2) log2q−1 times faster than binary method for an elliptic curve over Fq.The key operation in Elliptic Curve Cryptosystems(ECC) is point scalar multiplication. Making use of Frobenius endomorphism, Muller and Smart proposed two efficient algorithms for point scalar multiplications over even or odd finite fields respectively. This paper reduces the corresponding multiplier by modulo τ k−1+…+τ+1 and improves the above algorithms. Implementation of our Algorithm 1 in Maple for a given elliptic curve shows that it is at least as twice fast as binary method. By setting up a precomputation table, Algorithm 2, an improved version of Algorithm 1, is proposed. Since the time for the precomputation table can be considered free, Algorithm 2 is about (3/2) log2 q−1 times faster than binary method for an elliptic curve over F q.