## CryptoDB

### Muxiang Zhang

#### Publications

Year
Venue
Title
2007
EPRINT
Recently, Tanaka proposed an identity based non-interactive key sharing scheme and its corresponding identity based encryption scheme based on the intractability of integer factorization and discrete logarithm. The proposed identity based non-interactive key sharing scheme is similar to the well-known Maurer-Yacobi public key distribution scheme but the computational complexity for private key generation can be significantly reduced. It is also claimed that the proposed identity based non-interactive key sharing scheme is "collusion-attack free", i.e., secure against collusion attacks. In this paper, we analyze the security of the "collusion-attack free" identity based non-interactive key sharing scheme. First, we show that, without colluding with other users, a single user can recover some of the secret information of the private key generator. Then we show that a small group of users can collude to recover all of the secret information held by the private key generator. Thus, the "collusion-attack free" identity based non-interactive key sharing scheme can be completely compromised by collusion attacks.
2004
ASIACRYPT
2004
EPRINT
We investigate efficient protocols for password-authenticated key exchange based on the RSA public-key cryptosystem. To date, most of the published protocols for password-authenticated key exchange were based on Diffie-Hellman key exchange. It appears inappropriate to design password-authenticated key exchange protocols using RSA and other public-key cryptographic techniques. In fact, many of the proposed protocols for password-authenticated key exchange based on RSA have been shown to be insecure; the only one that remains secure is the SNAPI protocol. Unfortunately, the SNAPI protocol has to use a prime public exponent $e$ larger than the RSA modulus $n$. In this paper, we present a new password-authenticated key exchange protocol, called {\em PEKEP}, which allows using both large and small prime numbers as RSA public exponents. Based on number-theoretic techniques, we show that the new protocol is secure against the $e$-{\em residue attack}, a special type of off-line dictionary attack against RSA-based password-authenticated key exchange protocols. We also provide a formal security analysis of PEKEP under the RSA assumption and the random oracle model. On the basis of PEKEP, we present a computationally-efficient key exchange protocol to mitigate the burden on communication entities.
2003
EPRINT
This paper analyses the authentication and key agreement protocol adopted by Universal Mobile Telecommunication System (UMTS), an emerging standard for third generation (3G) wireless communications. The protocol, known as {\em 3GPP AKA}, is based on the security framework of GSM and provides significant enhancement to address and correct real and perceived weaknesses in GSM and other wireless communication systems. In this paper, we show that 3GPP AKA is vulnerable to a variant of false base station attack. The vulnerability allows an adversary to re-direct user traffic to an unintended network. It also allows an adversary to use authentication vectors obtained from a corrupted network to impersonate all other networks. In addition, we show that the need of synchronization between a mobile station and its home network incurs considerable difficulty for the normal operation of 3GPP AKA. To provide further enhancement on 3GPP AKA, we present an authentication and key agreement protocol which defeats re-direction attack and drastically lowers the impact of network corruption. The proposed protocol also eliminates synchronization between a mobile station and its home network. Following the multi-party simulatability approach, we have developed a formal model of security for symmetric-key based authentication and key agreement protocols in the mobile setting. Within this model, we have analyzed the security of our protocol against a powerful adversary having full control of the communication channels between a user and a network.
2000
CRYPTO
2000
FSE
2000
JOFC

#### Coauthors

Christopher Carroll (1)
Agnes Hui Chan (2)