In this paper we investigate the image authentication system SARI, proposed by C.Y. Lin and S.F. Chang [1], that distinguishes JPEG compression from malicious manipulations. In particular, we look at the image digest component of this system. We show that if multiple images have been authenticated with the same secret key and the digests of these images are known to an attacker, Oscar, then he ...

We propose techniques that allow construction of robust threshold RSA signature schemes that can work without a trusted dealer using known key generation protocols and is as efficient as the best previous schemes. We do not need special conditions on the RSA modulus, extra complexity or set-up assumptions or random oracles. An “optimistic” variant of the scheme is even more efficient in case no...

We propose a new unidirectional proxy re-encryption scheme based on lattices. Our construction is collusion-safe and does not require any trusted authority for the re-encryption key generation. We extend a recent trapdoor definition for a lattice of Micciancio and Peikert. Our proxy re-encryption scheme is provably CCA-1 secure in the selective model under the standard assumption.

We propose a new unidirectional proxy re-encryption scheme based on the hardness of the LWE problem. Our construction is collusionsafe and does not require any trusted authority for the re-encryption key generation. We extend a recent trapdoor definition for a lattice of Micciancio and Peikert. Our proxy re-encryption scheme is provably CCA-1 secure in the selective model under the LWE assumption.

With the popularization of wireless network, security issue is more and more important. When IEEE 802.11i draft proposed TKIP, it is expected to improve WEP (Wired Equivalent Privacy) on both active and passive attack methods. Especially in generating and management of secret keys, TKIP uses more deliberative attitude to distribute keys. Besides, it just upgrades software to accomplish these fu...

Generating secret keys using physical properties of the wireless channel has recently become a popular research area. The main security assumption of these protocols is that a sufficiently distant adversary is unable to guess a generated secret due to the unpredictable behavior of multipath signal propagation. In this paper, we introduce a practical and efficient man-in-the-middle attack agains...

Many techniques have been proposed to generate keys including text passwords, graphical passwords, biometric data and etc. Most of these techniques are not resistant to coercion attacks in which the user is forcefully asked by an attacker to generate the key to gain access to the system or to decrypt the encrypted file. We present a novel approach in generating cryptographic keys to fight again...

In this paper, we pioneer a key security level gradation scheme which is proved to efficient to counteract Iterative-Encrypting-Attack against RSA. And we make it clear that the bug which hides after the traditional key generation algorithm is exploited by Iterative-EncryptingAttack and weakens RSA security, and that the case can be improved if the traditional key generation algorithm is modifi...

Securing the confidential data transferred via wireless network remains a challenging problem. It is paramount to ensure that data are accessible only by the legitimate users rather than by the attackers. One of the most serious threats to organization is jamming, which disrupts the communication between any two pairs of nodes. Therefore, designing an attack-defending scheme without any packet ...

This paper presents a protocol called SAKE (Software Attestation for Key Establishment), for establishing a shared key between any two neighboring nodes of a sensor network. SAKE guarantees the secrecy and authenticity of the key that is established, without requiring any prior authentic or secret information in either node. In other words, the attacker can read and modify the entire memory con...