Autotomic Signatures

Related Concepts

Digital Signatures

Definition

Digital signature security is defined as an interaction between a signer ${\mathcal{S}}_{\mathit{sk}}$, a verifier ${\mathcal{V}}_{\mathit{pk}}$, and an attacker $\mathcal{A}$. $\mathcal{A}$ submits adaptively to ${\mathcal{S}}_{\mathit{sk}}$ a sequence of messages ${m}_{1},\ldots, {m}_{q}$ to which ${\mathcal{S}}_{\mathit{sk}}$ replies with the signatures $U =\{ {\sigma }_{1},\ldots, {\sigma }_{q}\}$. Given U, $\mathcal{A}$ attempts to produce a forgery, defined as a pair $(m',\sigma ')$ such that ${\mathcal{V}}_{\mathit{pk}}(m',\sigma ')$=true and $\sigma '\not\in U$. The traditional approach consists in hardening ${\mathcal{S}}_{\mathit{sk}}$ against a large query bound q. Rather than hardening $\mathcal{S}_{sk}$, autotomic signatures weaken $\mathcal{A}$ by preventing him from influencing ${\mathcal{S}}_{\mathit{sk}}$’s input: upon receiving m _i , ${\mathcal{S}}_{\mathit{sk}}$will generate a fresh...