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Improving the exact security of digital signature schemes

2002; Springer Science+Business Media; Volume: 15; Issue: 1 Linguagem: Inglês

10.1007/s00145-001-0005-8

1432-1378

Silvio Micali, Leonid Reyzin,

Cryptographic Implementations and Security

We put forward a new method of constructing Fiat-Shamir-like signature schemes that yields better "exact security" than the original Fiat-Shamir method. (We also point out, however, that such tight security does not make our modified schemes always preferable to the original ones. Indeed, there exist particularly efficient Fiat-Shamir-like schemes that, though only enjoying "loose security," by using longer keys may provably provide more security at a lower computational cost than their "tight-security" counterparts.)