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Provably Secure Untraceable Electronic Cash against Insider Attacks

2007; Institute of Electronics, Information and Communication Engineers; Volume: E90-A; Issue: 5 Linguagem: Inglês

10.1093/ietfec/e90-a.5.980

1745-1337

Yoshikazu Hanatani, Yuichi Komano, Kazuo Ohta, Noboru Kunihiro,

Chaos-based Image/Signal Encryption

Although a great deal of research has been done on electronic cash schemes with blind multisignatures to prevent an insider attack, there is no discussion of a formal security model in the literature. Firstly we discussed the security model of e-cash schemes based on the blind multisignature scheme against a (restricted) attack model and proposed a concrete scheme proven to be secure in the model [1]; however, this attack model disallows an attacker from corrupting an issuing bank and shops in the forgery game. In this paper, first, we reconsider the security model to remove the restriction of the attack model. Second, we propose a new untraceable e-cash scheme with a blind multisignature scheme and prove that the proposed scheme is secure against the (non-restricted) attacks under the DDH assumption in the random oracle model.