*06:19* [Job][New]
PhD Student, *PhD positions at CTIC, Aarhus University, Denmark, Northern Europe*
A number of attractive PhD grants is available at Center for the Theory of Interactive Computation (CTIC), which is a Sino-Danish research center. The center is a collaboration between the Computer Science Department at Aarhus University, Denmark and IIIS, Tsinghua University, Beijing, China, and is led by Professor Andrew Chi-Chih Yao, Tsinghua University, and Professor Peter Bro Miltersen, Aarhus University. The positions are within the focus areas of the center which are computational complexity theory, cryptography, quantum informatics, and algorithmic game theory. See also http://ctic.au.dk/.The successful candidates will obtain their degrees from Aarhus University and are expected to do most of their studies there, but also do stays at IIIS.

To be admitted as a PhD student at Aarhus University Graduate School of Science and Technology PhD program requires between 3 and 5 years of study, depending on the background of the candidate. The minimum requirement for applying is a Bachelor\\\'s degree. Applications should be entered at the Aarhus Graduate School of Science and Technology (GSST) web interface, where PhD applicants will also find detailed and relevant information about the application process, deadlines, financing etc.: http://talent.au.dk/phd/scienceandtechnology/.

To obtain further information before applying, please email *ctic (at) cs.au.dk.* The next application deadline is May 1st, 2014.

*06:19* [Job][New]
Ph.D. Scholarship in Computer Science (3 years full time), *University of Wollongong, Australia*
The Centre for Computer and Information Security Research (CCISR) at the University of Wollongong, Australia, is looking for a high caliber PhD student to work in the topic of \\\"Post-quantum Cryptography\\\".The topic includes the following sub-topics:

- lattice-based cryptography,

- multivariate cryptography,

- code-based cryptography,

- quantum computing.

Candidates are required to have a good background in mathematics.

All the decisions made will be final and there is no appeal procedure.

Ideally, it is expected that the candidate will start the PhD candidature by August 2014.

Interested candidates should send their complete CV, which includes their research experience and publication to Dr. Thomas Plantard (*thomaspl (at) uow.edu.au*).

Any questions regarding this position should be directed to

Prof. Willy Susilo (*wsusilo (at) uow.edu.au*) or Dr. Thomas Plantard (*thomaspl (at) uow.edu.au*).

*21:17* [Pub][ePrint]
High Parallel Complexity Graphs and Memory-Hard Functions, by Joel Alwen and Vladimir Serbinenko
Motivated by growing importance of parallelism in modern computational systems, we introduce a very natural generalization to a parallel setting of the powerful (sequential) black pebbling game over DAGs. For this new variant, when considering pebbling graphs with with multiple disconnected components (say when modelling the computation of multiple functions in parallel), we demonstrate a significant shortcoming of the two most common types of complexity measures for DAGs inherited from the sequential setting (namely S-complexity and ST-complexity). Thus, to ensure the applicability of the new pebbling game as a tool for proving results about say the \\emph{amortized} hardness of functions being repeatedly evaluated, we introduce a new complexity measure for DAGs called \\emph{cumulative complexity} (CC) and show how it overcomes this problem.\\\\With the aim of facilitating the new complexity lower-bounds in parallel settings we turn to the task of finding high CC graphs for the parallel pebbling game. First we look at several types of graphs such as certain stacks of superconcentrators, permutation graphs, bit-reversal graphs and pyramid graphs, which are known to have high (even optimally so) complexity in the sequential setting. We show that all of them have much lower parallel CC then one could hope for from a graph of equal size. This motivates our first main technical result, namely the construction of a new family of constant in-degree graphs whose parallel CC approaches maximality to within a polylogarithmic factor.\\\\

The second contribution of this work is to demonstrate an application of these new theoretical tools, in particular to the field of cryptography. Memory-hard function (MHF), introduced by Percival~\\cite{Per09}, have the intuitive goal of leverage the relatively high cost of memory in integrated circuits compared to general purpose computers in order to decrease the attractiveness of using custom circuits to mount brute-force attacks. We provide a new formalization for key property of such functions (overcoming problems with the approach of~\\cite{Per09}) using a new type of \\emph{amortized} computational hardness for families of functions in the (parallel) random oracle model. We motivate the hardness definition by showing how it provides an immediate lower-bound on the monetary cost of repeatedly evaluating such functions in several real-world (parallel) computational environments (e.g. FPGAs, ASICs, Cloud Computers). Indeed, in practice such devices are often the most cost effective means for mounting large-scale brute-force attacks on security relevant functions (such as say Proofs-of-Work and the hash functions used to obscure stored passwords in login servers). As the main technical result of this section, for the family of functions $f_G$ (over strings) characterized via a given DAG $G$, we prove a lower-bound on the hardness of $f_G$ in terms of the parallel CC of $G$. In consequence, we obtain the first provably secure (and intuitively sound) MHF.

*14:46* [Job][New]
PhD scholarship, *University of Auckland, New Zealand*
The Inaugural Sir Vaughan F.R. Jones PhD ScholarshipThis prestigious scholarship will fund the research in any area of mathematics of a PhD student supervised by a member of the Department of Mathematics. Selection is based purely on the record and research promise of the candidate. The Jones Scholarship offers an annual stipend of NZ$25,000 (tax free), plus fees, for three years of PhD study.

New Zealand mathematician Vaughan Jones, KNZM FRS FRSNZ FAAAS, was awarded the Fields Medal in 1990. He is Distinguished Professor at both the University of Auckland and Vanderbilt University. He is best known for his work on knot (Jones) polynomials and von Neumann algebras.

Interested candidates are encouraged to contact members of the Department informally concerning possible research projects. For public key cryptography or number theory, please contact Steven Galbraith.

Full applications must be received by August 30, 2014.

*10:55* [Job][New]
Researcher in Boolean Functions, *Reliable Communication Group, Department of Informatics, University of Bergen, Norway*
The Reliable Communication Group at the University of Bergen invites applications for a 3-year researcher position in Boolean functions. The position is supposed to start in October 2014. The candidate is expected to have PhD degree in mathematics or computer science or related disciplines, and have considerable publications in discrete functions.

We are seeking an active researcher with expertise in Boolean functions, discrete mathematics and symmetric cryptography to work within the recently funded project “Discrete functions and their applications in cryptography and mathematics”. The prime objectives of this project are Boolean functions with optimal resistance to various cryptographic attacks (differential, linear, algebraic et al.) and their applications in discrete mathematics (such as commutative semifields, o-polynomials, difference sets, dual hyperovals, regular graphs, m-sequences, codes et al.).

*15:32* [Job][New]
Doctoral Student, *Technische Universität Darmstadt, Germany*
The Engineering Cryptographic Protocols Group at TU Darmstadt is looking for a doctoral student in **Engineering Cryptographic Protocols for Cloud Computing**.Our group is involved in the two main research centers for IT security in Darmstadt, the Center for Advanced Security Research Darmstadt (CASED) and the European Center for Security and Privacy by Design (EC SPRIDE). We develop new methods and tools to optimize and automatically generate cryptographic protocols. See http://encrypto.de for details.

The candidate will work in the EU FP 7 research project PRACTICE (Privacy-Preserving Computation in the Cloud), http://www.practice-project.eu, with the goal of developing, optimizing, and automatically generating secure computation protocols for cloud computing.

The candidate is expected to have a completed Master (or equivalent) degree with excellent grades in IT security, computer science, electrical engineering, mathematics, or a closely related field. Solid knowledge in IT security, applied cryptography, and programming skills is required. Additional knowledge in cryptographic protocols, parallel computing, compiler construction, programming languages, and software engineering is a plus.

Review of applications starts immediately until the position is filled.

Please consult the webpage given below for more details and how to apply.