IACR News item: 17 December 2013
Aggelos Kiayias, Qiang Tang
ePrint Reportfunctions? This question appears to be fundamentally hard to address
since in this setting the owner of the key {\\em is} the adversary:
she wishes to share a program or device that (potentially only
partly) implements her main cryptographic functionality. Given that
she possesses the cryptographic key, it is impossible for her to be
{\\em prevented} from writing code or building a device that uses
that key. She may though be {\\em deterred} from doing so.
We introduce {\\em leakage-deterring} public-key cryptographic
primitives to address this problem. Such primitives have the feature
of enabling the embedding of owner-specific private data into the
owner\'s public-key so that given access to {\\em any} (even
partially functional) implementation of the primitive, the recovery
of the data can be facilitated. We formalize the notion of
leakage-deterring in the context of encryption, signature, and
identification and we provide efficient generic constructions that
facilitate the recoverability of the hidden data while retaining
privacy as long as no sharing takes place.
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