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00:17 [Pub][ePrint] Transposition of AES Key Schedule, by Jialin Huang, Xuejia Lai

  In this paper, we point out a new weakness of the AES key schedule by revisiting an old observation exploited by many known attacks. We also discover a major cause for this weakness is that the column-by-column word-wise property in the key schedule matches nicely with the MixColumns operation in the cipher\'s diffusion layer. Then we propose a new key schedule by minor modification to increase the security level for AES. First, it reduces the number of rounds that some attacks are effective, such as SQUARE attacks and meet-in-the-middle attacks; Second, it is interesting that our new key schedule also protects AES from the most devastating related-key differential type attacks, which work against AES-192 and AES-256 with the full number of rounds. Compared with the original key schedule, ours just does a transposition on the output matrix of the subkeys. Compared with other proposed modifications of AES key schedule, our modification adds no non-linear operations, no need to complicate the diffusion method, or complicate the iteration process of generating subkeys. Finally, our results suggest that the route of diffusion propagation should get more attention in the design of key schedules.

00:17 [Pub][ePrint] Dual Form Signatures: An Approach for Proving Security from Static Assumptions, by Michael Gerbush and Allison Lewko and Adam O\'Neill and Brent Waters

  In this paper, we introduce the abstraction of Dual Form Signatures as a useful framework for proving security (existential unforgeability) from static assumptions for schemes with special structure that are used as a basis of other cryptographic protocols and applications. We demonstrate the power of this framework by proving security under static assumptions for close variants of pre-existing schemes:


\\item the LRSW-based Camenisch-Lysyanskaya signature scheme

\\item the identity-based sequential aggregate signatures of Boldyreva, Gentry, O\'Neill, and Yum.


The Camenisch-Lysyanskaya signature scheme was previously proven only under the interactive LRSW assumption, and our result can be viewed as a static replacement for the LRSW assumption. The scheme of Boldyreva, Gentry, O\'Neill, and Yum was also previously proven only under an interactive assumption that was shown to hold in the generic group model. The structure of the public key signature scheme underlying the BGOY aggregate signatures is quite distinctive, and our work presents the first security analysis of this kind of structure under static assumptions.

We view our work as enhancing our understanding of the security of these signatures, and also as an important step towards obtaining proofs under the weakest possible assumptions.

Finally, we believe our work also provides a new path for proving security of signatures with embedded structure. Examples of these include:

attribute-based signatures, quoteable signatures, and signing group elements.

09:58 [PhD][New] Christophe Giraud: Attacks on embedded cryptosystems and corresponding countermeasures

  Name: Christophe Giraud
Topic: Attacks on embedded cryptosystems and corresponding countermeasures
Category: implementation

Description: Side channel attacks are a very powerful tool used to recover secrets stored in embedded devices such as smart cards. By analysing the power consumption, the electromagnetic radiations or by disturbing the device, an attacker can easily obtain secret keys used by non protected embedded cryptosystems. The subject of this thesis is to extend the impact of side channel analysis by presenting new attacks and new countermeasures. The latter must have a very small impact on the performance of the algorithm since the embedded environment is limited in terms of both memory space and computation power.\r\nFirstly, we focus on Power Analysis countermeasures. We describe a method to protect the elliptic curve scalar multiplication from Simple Analysis. Then, we propose a countermeasure against Di?erential Analysis on DES and AES and a generic method to protect S-Box access. Secondly, we deal with Fault Attacks. After presenting a general overview of this ?eld, we propose new fault attacks on cryptosystems such as AES and XTR which haven’t yet been successfully impacted. Then, we improve some existing attacks on several signature schemes in order to be able to put these attacks into practice. Finally, we present new countermeasures on XTR and on the RSA cryptosystem.[...]

04:32 [Event][New] QCRYPT 2012: 2nd Annual Conference on Quantum Cryptography

  Submission: 20 May 2012
Notification: 6 July 2012
From September 10 to September 14
Location: Singapore, Singapore
More Information:

18:51 [PhD][New] Nicolás González-Deleito: Trust relationships in exchange protocols

  Name: Nicolás González-Deleito
Topic: Trust relationships in exchange protocols
Category: cryptographic protocols

18:50 [PhD][New] Yves Roggeman

  Name: Yves Roggeman

18:49 [PhD][New] Olivier Markowitch: Non-repudiation protocols

  Name: Olivier Markowitch
Topic: Non-repudiation protocols
Category: cryptographic protocols

18:49 [PhD][New] Gilles Piret: Block Ciphers: Security Proofs, Cryptanalysis, Design, and Fault Attacks

  Name: Gilles Piret
Topic: Block Ciphers: Security Proofs, Cryptanalysis, Design, and Fault Attacks
Category: secret-key cryptography

18:46 [Job][Update] Post-Doc, Technical University Denmark, Copenhagen


Postdoc within the area of Symmetric Cryptography

Applications are invited for an 18 month (with a possible extension of 6 months) Postdoc position at the Danish-Chinese Center for Applications of Algebraic Geometry in Coding and Cryptology. The center is located at the Department of Mathematics at the Technical University of Denmark. The position is available from July 2012 or earliest thereafter.


The candidate should have a PhD degree or academic qualifications equivalent to the PhD level, and should have a strong background in symmetric cryptography. This is usually demonstrated by having publications in well established journals and/or conferences.

As it is essential for the project to establish research connections with China, applicants are expected to be willing to actively establish these connections. This ideally includes one or several visits to the East China Normal University.

Salary and terms of employment

The appointment will be based on the collective agreement with the Confederation of Professional Associations. The allowance will be agreed with the relevant union.

The period of employment is 18 months.

Further information

Further information about the project may be reached by contacting Associate Professor Gregor Leander, tel. (+45) 4525 3055, g.leander (at)


We must have your online application no later than 31 May 2012. See for details.

18:45 [Job][New] Research Fellow, Nanyang Technological University, Singapore

  Physical Analysis and Cryptographic Engineering (PACE) Labs at Nanyang Technological University are seeking 2 Research Scientists in the area of side-channel and fault attacks. The newly founded lab is dedicated to all aspects of side-channel and fault attacks and offers brand-new facilities, a very diverse international research environment, and the opportunity to undertake independent research.

Candidates shall hold, or expect to obtain, a Ph.D. in Computer Sciences, Electrical Engineering, Mathematics or a related field. A solid background in one or several areas of Information Theory, Digital Signal Processing, Statistics, Mutual Information Analysis, DEMA attacks, fault attacks, practical measurements, lightweight implementations (software and/or hardware) would be considered an advantage.

Starting date is in May 2012 and funding is available for 3 years, thus the contract will be for up to 3 years (depending on the successful candidates\' ability to start working in Singapore).

Salaries are competitive and are determined according to the successful applicants\' accomplishments, experience and qualifications.

Interested applicants with a strong publication record in the fields of side-channel and/or fault attacks are encouraged to submit their application including:

1) cover letter,

2) detailed CV,

3) filled personal particulars form*, and

4) names/contact emails of 2 references

to Prof. Axel Poschmann aposchmann (at)

Review of applications starts immediately and will continue until positions are filled.

* accesible via

18:45 [Event][New] crypt@b-it 2012: crypt@b-it 2012: Summer school on Cryptography

  From July 16 to July 20
Location: Bonn, Germany
More Information: