*17:37* [PhD][New]
Jens Zumbrägel: Public-key cryptography based on simple semirings
Name: Jens Zumbrägel

Topic: Public-key cryptography based on simple semirings

Category: public-key cryptography

Description: The discrete logarithm problem is the basic ingredient of many\r\n public-key cryptosystems. It can be stated as follows: Given a\r\n cyclic group (*G*,?) of order *n*, a\r\n generator *g* of *G*, and another\r\n element *h*?*G*, find the unique\r\n integer *a*?[0,*n*) such that\r\n *h*=*g*ˆ*a*. The integer *a* is called\r\n the *discrete logarithm* of\r\n *h* to the base *g*.

\r\n \r\nThere are key agreement protocols, public-key encryption schemes,\r\n and digital signatures employing the discrete logarithm problem.\r\n One example is the Diffie-Hellman key agreement protocol. It allows\r\n two parties, A and B, to agree on a secret key over an insecure\r\n channel. In order to achieve this goal they fix a finite cyclic\r\n group *G* and a generator *g* of *G*. Then A and B\r\n pick random integers *a*,*b* respectively and exchange\r\n *h*A=*g*ˆ*a*\r\n and *h*B=*g*ˆ*b*. Finally they\r\n compute *h*Bˆ*a*=*g*ˆ*ba*\r\n and *h*Aˆ*b*=*g*ˆ*ab*, and\r\n since *g*ˆ*ab*=*g*ˆ*ba* this element\r\n can be used as their secret key.

\r\n\r\nIt is clear that solving the underlying discrete logarithm problem\r\n is sufficient for breaking the Diffie-Hellman protocol. For this\r\n reason one has been searching for groups in which the discrete\r\n logarithm problem is considered to be a computationally hard\r\n problem. Among the groups that have been proposed as candidates are\r\n the multiplicative group of a finite field and the group over an\r\n elliptic curve. It should however be pointed out that the\r\n infeasibility of the discrete logarithm problem has not been proved\r\n in any concrete group.

\r\n\r\nDiscrete logarithm based cryptosystems can be generalized in the\r\n framework of *semigroup actions* (see e.[...]

*07:36* [Job][Update]
Lecturer, *Queensland University of Technology, Brisbane, Australia*
The Queensland University of Technology (QUT) in Brisbane, Australia, invites applications for full-time Lecturer positions starting in 2012. Up to nine positions are available in the Science and Engineering Faculty.

The Science and Engineering Faculty at QUT has an active research group in cryptography, network security, and digital forensics, with a leading national profile and strong international links.

Applicants should have completed (or be under examination for) a PhD and be early career researchers (less than three years in an academic role). Appointee(s) will develop and maintain an active research program, teach at undergraduate and graduate levels, supervise research students, and participate in QUT\\\'s Early Career Academic Development program.

*21:17* [Pub][ePrint]
On a CCA2-secure variant of McEliece in the standard model, by Edoardo Persichetti
We consider public-key encryption schemes based on error-correctingcodes that are IND-CCA2 secure in the standard model. We analyze a system due

to Dowsley, Muller-Quade and Nascimento. We then show how to instantiate the

Rosen-Segev framework with the McEliece scheme.

*12:59* [Job][New]
Postdoctoral Research Assistant in Cryptography, *Dept Computer Science, University of Bristol*
Based in the Cryptography group which has grown considerably in the last year, you will be an additional researcher in one of the following areas:•Analysis of “real world” protocols

•Formal Methods applied to security protocols

•Fully Homomorphic Encryption

•Lattice Based Cryptography

•Provable Security, i.e. Protocol and Mechanism design

The post is funded by an ERC Advanced Grant awarded to Prof. Nigel Smart.

The expected starting date will be as soon as possible depending on the your circumstances.

Please apply using the Online System linked to from the link below. We cannot accept applications via email.

*18:10* [PhD][New]
Côme Berbain: Analyse et conception d\'algorithmes de chiffrement à flot
Name: Côme Berbain

Topic: Analyse et conception d\'algorithmes de chiffrement à flot

Category: secret-key cryptography

Description: The primary goal of cryptography is to protect the confidentiality of data and communications. Stream ciphers is one of the two most popular families of symmetric encryption algorithms that allow to guaranty\r\nconfidentiality and to achieve high performances.

\r\n\r\nIn the first part of this thesis, we present different cryptanalysis techniques against stream ciphers: correlation\r\nattack against the stream cipher GRAIN, guess and determine attack against the BSG mechanism, algebraic attack against special\r\nkinds of non-linear feedback shift registers, and chosen IV attack against a reduced version of the stream cipher SALSA.

\r\n\r\nIn a second part, we focus on proofs of security for stream ciphers: we introduce the new algorithm QUAD and give some \r\nprovable security arguments in order to link its security to the conjectured intractability of Multivariate Quadratic problem. We also try to extend the security requirements of stream ciphers to the case where initialisation values (IV) are used: we present a construction which allows us\r\nto build a secure IV dependent stream cipher from a number generator and apply it to QUAD, which becomes the first IV dependent\r\nstream cipher with provable security arguments. We also present the algorithms DECIM and SOSEMANUK, to which we made\r\ndesign contributions.

\r\n\r\nFinally in a third part, we present efficient software and hardware implementations of the QUAD algorithm.

[...]

*18:09* [Job][New]
M.Sc. and Ph.D. positions with scholarship, *Koç University, Turkey*
Want to store your data online securely? Want a fair Internet? What about outsourcing your job while still being assured of the result?

If you want to secure the cloud through the use of provable cryptographic techniques, then you should definitely apply to the Cryptography, Security & Privacy Research Group at Koç University, ?stanbul, Turkey. We have multiple openings for both M.Sc. and Ph.D. level applications. **All** accepted applicants will receive competitive scholarships.

Koç University has a beautiful campus in the middle of a forest, with a nice view of the Black Sea and the Bosporus, and is very close to the Istanbul city center. The application deadline is 15th of April for early applications and 15th of June for late applications.

For more information about our group, visit

http://crypto.ku.edu.tr

For applying online, visit

http://gsse.ku.edu.tr

Late applications will be considered in exceptional cases.