International Association for Cryptologic Research

# IACR News Central

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Further sources to find out about changes are CryptoDB, ePrint RSS, ePrint Web, Event calender (iCal).

2012-10-07
21:17 [Pub][ePrint]

Transaction pseudonyms with implicit attributes are a novel approach to multilevel linkable transaction pseudonyms. We extend earlier work of Juels and Pappu on reencryption-based transaction pseudonyms, by developing new mechanisms for controlled pseudonym linkability.

This includes mechanisms for cooperative, stepwise re-identication

as well as individual authentication of pseudonyms. Our proposal makes

use of efficient techniques from the area of secure multiparty computation and cryptographically secure PRNGs.

21:17 [Pub][ePrint]

In all of existing efficient proofs of knowledge of a solution to the Inhomogeneous Small Integer Solution ISIS problem, the knowledge extractor can only output a vector that is about $\\sqrt{n}$ times longer than the witness possessed by the prover. As a consequence, in many cryptographic schemes that use these proof systems as building blocks, there exists a gap between the hardness of solving the underlying ISIS problem and the hardness used in the security reductions. In this paper, we generalize Stern\'s protocol to obtain two statistical zero-knowledge proofs of knowledge for the ISIS problem (in the $l_\\infty$ norm) that remove this gap. Our result yields the potential of relying on weaker security assumptions for various lattice-based cryptographic constructions. As applications of our proof system, we introduce a concurrently secure identity-based identification scheme based on the worst-case hardness of the $\\mathrm{SIVP}_{\\widetilde{O}(n^{1.5})}$ problem (in the $l_2$ norm) in general lattices in the random oracle model, and an efficient statistical zero-knowledge proof of plaintext knowledge with small constant gap factor for Regev\'s encryption scheme.

2012-10-04
20:25 [Event][New]

Submission: 10 December 2012
From June 2 to June 3
Location: Austin, United States

2012-10-03
17:11 [News]

NIST has announce Keccak as SHA-3 winner. You find more information about Keccak at http://keccak.noekeon.org/ The full statement of the NIST is found at the link below.

14:53 [Event][New]

Submission: 25 January 2013
From May 6 to May 7
Location: Gebze, Turkey

2012-10-02
15:17 [Pub][ePrint]

In this paper we present an attack on a fully homomorphic encryption scheme on PKC2010.

We construct a modi¯ed secret key, a modi¯ed decryption algorithm and a subset of the ciphertext

space. When the ciphertext is from the subset, we can correctly decrypt it by our modi¯ed secret key

and modi¯ed decryption algorithm. We also discuss when our modi¯ed decryption algorithm is e±cient,

and when the subset is not negligible.

15:17 [Pub][ePrint]

Aggregate signature is public-key signature that allows anyone to aggregate different signatures generated by different signers on different messages into a short aggregate signature. Although aggregate signatures have many applications like secure routing protocols and software module authentications, it is not easy to devise a suitable aggregate signature scheme that satisfies the conditions of real applications such that the size of public keys should be short, the size of aggregate signatures should be short, and the aggregate signing and aggregate verification should be efficient.

In this paper, we propose two aggregate signature schemes based on the Camenisch-Lysyanskaya signature scheme that sufficiently satisfy the conditions of real applications. At first, we construct an efficient sequential aggregate signature scheme and prove its security under the LRSW assumption without random oracles. The proposed scheme has the shortest size of public keys among the sequential aggregate signature schemes and very short size of aggregate signatures. Additionally, the aggregate verification of this scheme is very efficient since it only requires constant number of pairing operations and $l$ number of exponentiations where $l$ is the number of signers in an aggregate signature. Next, we construct an efficient synchronized aggregate signature scheme and prove its security under the LRSW assumption in the random oracle model. The proposed scheme has very short size of public keys and the shortest size of aggregate signatures among the synchronized aggregate signature schemes. The signing and aggregate verification is also very efficient since these requires constant number of pairing operations and $l$ number of exponentiations.

Furthermore, a signer of our aggregate signature schemes can use two mode of aggregation sequential\'\' and synchronized\'\' at the same time just using the same private key and the public key since the private keys and the public keys of two schemes are the same.

14:26 [Job][New]

The Laboratory for Security and Cryptography (LASEC) at EPFL is hiring a post doctoral researcher. Applicants are encouraged to apply to job_lasec (at) epfl.ch by sending a detailed CV and a research plan.

LASEC is active in research on cryptography and security. More specifically, our main interests span (but are not limited to) the following:

• Cryptographic analysis

• Design of cryptographic algorithms and protocols

• Lightweight cryptography

• Secure communication

• Wireless security

• Composability and setup assumptions

• Methodology and theory for cryptography

• Number theory and cryptography.

The selection of applicants will be made on a competitive basis.

Besides conducting top-quality research, postdocs are required to participate the the lab activities such as training students at all levels, running projects, fund raising, etc.

EPFL is a top-ranked research and teaching institution that attracts some of the best intellects in the world. EPFL offers excellent facilities, environment, and salaries. The EPFL campus is a multi cultural, idyllic spot overlooking Lake Geneva and facing the Alps.

14:26 [Job][New]

The Laboratory for Security and Cryptography (LASEC) and the Laboratory for Cryptologic Algorithms (LACAL) at EPFL are hiring PhD students for Fall 2013. Applicants are encouraged to apply to the EDIC doctoral school (the application deadline is January 15, 2013) and, in parallel, to notify us at job_lasec (at) epfl.ch.

LASEC and LACAL are active in research on cryptography and security. More specifically, our main interests span (but are not limited to) the following:

• Efficient cryptologic calculations

• Cryptographic analysis

• Design of cryptographic algorithms and protocols

• Lightweight cryptography

• Secure communication

• Wireless security

• Composability and setup assumptions

• Methodology and theory for cryptography

• Number theory and cryptography.

The selection of applicants will be made on a competitive basis.

EPFL is a top-ranked research and teaching institution that attracts some of the best intellects in the world. EPFL offers excellent facilities, environment, and salaries. The EPFL campus is a multi cultural, idyllic spot overlooking Lake Geneva and facing the Alps.

09:05 [Event][New]

From October 18 to October 18
Location: Bruges, Belgium

07:01 [Job][Update]

The Digital Security group at the Radboud University Nijmegen has a

vacancy for a full-time assistant professorship (Universitair Docent

UD in Dutch).

General information

Research in the group covers a range of topics including correctess

and security of software, smartcards and RFID, design and analysis of

security protocols, applied crypto, privacy and anonimity, quantum

logic and computing. Members of the group are also active in the

broader societal issues surrounding security & privacy, and regulary

carry out commercial contract research to apply and inspire high

The group runs a joint Master programme in Computer Security in

collaboration with the universities of Twente and Eindhoven, named the

Kerckhoffs Institute (www.kerckhoffs-institute.org). In Nijmegen the

Institute for Computing and Information Sciences runs Bachelor and

Master courses in Computer Science (Informatica) and Information

Science (Informatiekunde).

For this position we are looking for the best candidate in the broader

field of security, who can be a good addition to the group and has

good synergy with ongoing research in the group, who is a team player,

and who can teach computer security to a broad range of students.