Colluding Attacks to a Payment Protocol and Two Signature Exchange Schemes

Feng Bao

M. Magdalena Payeras–Capellà, Josep Lluís Ferrer Gomila, L. Huguet

Michèle Feltz

Yingyou Wen

By introducing signcryption technology into concurrent signature,a signcryption-based concurrent signature scheme was presented,which was proven to have the existential unforgeability against adaptive chosen messages attacks under the random oracle model,Based on this scheme,a fair exchange protocol was proposed,which could be used to exchange digital goods.This protocol did not need secure communications channel,in which two parties generate sym-metrical ambiguous signatures and individual keystones were released by themselves,which ensured the properties of confidentiality,ambiguousness and fairness,which made our protocol could be used in e-commerce payment,e-contract signing,mail authentication,etc.

Juan A. Garay, PHILIP D. MACKENZIE, Ke Yang

Jingwei Liu, Rong Xia Sun, Weidong Kou

This paper presents a simple partially blind signature scheme with low computation. By converse using the partially blind signature scheme, we build a simple fair e-payment protocol. In the protocol, two participants achieve the goals of exchanging their digital signatures from each other in a simple way. An advantage of this scheme is that this approach does not require the intervention of the third party in any case. The low-computation property makes our scheme very attractive for mobile client and smart-card implementation in many e-commerce applications.