1 research outputs found
Practical Strongly Invisible and Strongly Accountable Sanitizable Signatures
Sanitizable signatures are a variant of digital signatures where a designated party (the sanitizer) can
update admissible parts of a signed message. At PKC’17, Camenisch et al. introduced the notion of invisible
sanitizable signatures that hides from an outsider which parts of a message are admissible. Their security definition of
invisibility, however, does not consider dishonest signers. Along the same lines, their signer-accountability definition
does not prevent the signer from falsely accusing the sanitizer of having issued a signature on a sanitized message
by exploiting the malleability of the signature itself. Both issues may limit the usefulness of their scheme in certain
applications.
We revise their definitional framework, and present a new construction eliminating these shortcomings. In contrast
to Camenisch et al.’s construction, ours requires only standard building blocks instead of chameleon hashes with
ephemeral trapdoors. This makes this, now even stronger, primitive more attractive for practical use. We underpin
the practical efficiency of our scheme by concrete benchmarks of a prototype implementation