Get an update on changes of the IACR web-page here. For questions, contact newsletter (at) iacr.org. You can also receive updates via:
To receive your credentials via mail again, please click here.
You can also access the full news archive.
inherently difficult to analyze because their security analysis uses
rewinding. Certain cases of quantum rewinding are handled by the
results by Watrous (SIAM J Comput, 2009) and Unruh (Eurocrypt 2012),
yet in general the problem remains elusive. We show that this is not
only due to a lack of proof techniques: relative to an oracle, we show
that classically secure proofs and proofs of knowledge are insecure in
the quantum setting.
More specifically, sigma-protocols, the Fiat-Shamir construction, and
Fischlin\'s proof system are quantum insecure under assumptions that
are sufficient for classical security. Additionally, we show that for
similar reasons, computationally binding commitments provide almost no
security guarantees in a quantum setting.
To show these results, we develop the \"pick-one trick\", a general
technique that allows an adversary to find one value satisfying a
given predicate, but not two.
This paper introduces POE, a family of on-line ciphers that combines provable security against chosen-ciphertext attacks with pipelineability to support efficient implementations. POE combines a block cipher and an e-AXU family of hash functions. Different instantiations of POE are given, based on different universal hash functions and suitable for different platforms. Moreover, this paper introduces POET, a provably secure on-line AE scheme, which inherits pipelineability and chosen-ciphertext-security from POE and provides additional resistance against nonce-misuse attacks.
so far, most applications of this theory do not
require additional properties. Motivated by recent applications, we require global function fields
with the additional property that their zero class divisor groups contain at most a small number of $d$-torsion points. We capture this with the notion of torsion limit, a new asymptotic quantity for global function fields.
It seems that it is even harder to determine values of this new quantity than the Ihara constant.
Nevertheless, some non-trivial upper bounds are derived.
Apart from this new asymptotic quantity and bounds on it, we also introduce Riemann-Roch systems of equations. It turns out that this type of equation system
plays an important role in the study of several other problems in each of these areas: arithmetic secret sharing, symmetric bilinear complexity of multiplication in finite fields, frameproof codes and the theory of error correcting codes.
Finally, we show how our new asymptotic quantity, our bounds on it and Riemann-Roch systems can be used to improve results in these areas.
function built around the Merkle-Damgard hash function H. It supports
large [pseudo]random salt values ( 128-bit) and password lengths.
ZAP (or, equivalently, non-interactive zero-knowledge in the common random string model) from indistinguishability obfuscation and one-way functions.
NIWIs from indistinguishability obfuscation and one-way permutations.
The previous construction of ZAPs [Dwork and Naor, FOCS 00] was based on trapdoor permutations. The two previous NIWI constructions were based either on ZAPs and a derandomization-type complexity assumption [Barak, Ong, and Vadhan CRYPTO 03], or on a specific number theoretic assumption in bilinear groups [Groth, Sahai, and Ostrovsky, CRYPTO 06].