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2012-04-01
12:20 [Pub][JoC] Mercurial Commitments with Applications to Zero-Knowledge Sets

 

Abstract  We introduce a new flavor of commitment schemes, which we call mercurial commitments. Informally, mercurial commitments are standard commitments that have been extended to allow for soft decommitment. Soft decommitments, on the one hand, are not binding but, on the other hand, cannot be in conflict with true

decommitments.

We then demonstrate that a particular instantiation of mercurial commitments has been implicitly used by Micali, Rabin and

Kilian to construct zero-knowledge sets. (A zero-knowledge set scheme allows a Prover to (1) commit to a set S in a way that reveals nothing about S and (2) prove to a Verifier, in zero-knowledge, statements of the form xS and xS.) The rather complicated construction of Micali et al. becomes easy to understand when viewed as a more general construction

with mercurial commitments as an underlying building block.

By providing mercurial commitments based on various assumptions, we obtain several different new zero-knowledge set constructions.

  • Content Type Journal Article
  • Pages 1-29
  • DOI 10.1007/s00145-012-9122-9
  • Authors

    • Melissa Chase, Microsoft Research, Redmond, WA 98052, USA
    • Alexander Healy, Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
    • Anna Lysyanskaya, Department of Computer Science, Brown University, Providence, RI 02912, USA
    • Tal Malkin, Department of Computer Science, Columbia University, New York, NY 10027, USA
    • Leonid Reyzin, Department of Computer Science, Boston University, Boston, MA 02215, USA

    • Journal Journal of Cryptology
    • Online ISSN 1432-1378
    • Print ISSN 0933-2790

From: Wed, 28 Mar 2012 05:59:34 GMT




2012-03-30
08:05 [Job][Update] Ph.D scholarship, Newcastle University, UK

  A PhD scholarship is available at the School of Computing Science, Newcastle University, UK. The research will be in the area of security and applied cryptography. Topics include, but are not limited by, biometric encryption, digital forensics, authenticated key exchange, electronic voting, digital cash, anonymous auction, RFID authentication and distance bounding protocols and so on. The student is encouraged to choose or define a topic of his/her most interest and expertise.

The scholarship will cover the tuition fee, and provide a stipend of £14,790 per year for maintenance. The full amount is applicable to an EU student only. If you are a non-EU student with outstanding background, please contact Dr Feng Hao (feng.hao at ncl.ac.uk) for more details.

To apply, please send your CV and a brief research proposal (max 2 page) to Dr Feng Hao (feng.hao at ncl.ac.uk). For interested candidates, the application should be made as early as possible.

08:05 [Job][New] Ph.D scholarship, Newcastle University

  A PhD scholarship is available at the School of Computing Science, Newcastle University, UK. The research will be in the area of security and applied cryptography. Topics include, but are not limited by, biometric encryption, digital forensics, authenticated key exchange, electronic voting, digital cash, anonymous auction, RFID authentication and distance bounding protocols and so on. The student is encouraged to choose or define a topic of his/her most interest and expertise.

The scholarship will cover the tuition fee, and provide a stipend of £14,790 per year for maintenance. The full amount is applicable to an EU student only. If you are a non-EU student with outstanding background, please contact Dr Feng Hao (feng.hao at ncl.ac.uk) for more details.

To apply, please send your CV and a brief research proposal (max 2 page) to Dr Feng Hao (feng.hao at ncl.ac.uk). For interested candidates, the application should be made as early as possible.



2012-03-29
13:16 [PhD][Update] Joppe W. Bos: On the Cryptanalysis of Public-Key Cryptography

  Name: Joppe W. Bos
Topic: On the Cryptanalysis of Public-Key Cryptography
Category:public-key cryptography

Description: Nowadays, the most popular public-key cryptosystems are based on either the integer factorization or the discrete logarithm problem. The feasibility of solving these mathematical problems in practice are studied and techniques are presented to speed-up the underlying arithmetic on parallel architectures.

The fastest known approach to solve the discrete logarithm problem in groups of elliptic curves over finite fields is the Pollard rho method. The negation map can be used to speed up this calculation by a factor sqrt(2). It is well known that the random walks used by Pollard rho when combined with the negation map get trapped in fruitless cycles. We show that previously published approaches to deal with this problem are plagued by recurring cycles, and we propose effective alternative countermeasures. Furthermore, fast modular arithmetic is introduced which can take advantage of prime moduli of a special form using efficient "sloppy reduction." The effectiveness of these techniques is demonstrated by solving a 112-bit elliptic curve discrete logarithm problem using a cluster of PlayStation 3 game consoles: breaking a public-key standard and setting a new world record.

The elliptic curve method (ECM) for integer factorization is the asymptotically fastest method to find relatively small factors of large integers. From a cryptanalytic point of view the performance of ECM gives information about secure parameter choices of some cryptographic protocols. We optimize ECM by proposing carry-free arithmetic modulo Mersenne numbers (numbers of the form 2^M-1) especially suitable for parallel architectures. Our implementation of these techniques on a cluster of PlayStation 3 game consoles set a new record by finding a 241-bit prime factor of 2^1181-1.

A normal form for elliptic curves introduced by Edwards results in the fastest elliptic curve arithmetic in practice. Techniques to reduce the temporary storage and enhance the performance even f[...]


05:26 [Event][New] MIST 2012: Managing Insider Security Threats

  Submission: 31 July 2012
Notification: 31 August 2012
From November 8 to November 9
Location: Fukuoka, Japan
More Information: http://isyou.info/conf/mist12/




2012-03-28
15:42 [Event][New] ICISS 2012: 8th International Conference on Information Systems Security 2012

  Submission: 13 July 2012
Notification: 3 September 2012
From December 15 to December 19
Location: Guwahati, India
More Information: http://www.iitg.ernet.in/iciss2012/


11:01 [Event][Update] SCN 2012: 8th Conference on Security and Cryptography for Networks

  Submission: 3 May 2012
Notification: 15 June 2012
From September 5 to September 7
Location: Amalfi, Italy
More Information: http://scn.dia.unisa.it/