International Association
for Cryptologic Research

We are seeking an experienced and enthusiastic academic to augment our capabilities, capacity, and connections to industry in the rapidly evolving domain of cybersecurity. This opportunity is strongly motivated by the increasing need for cybersecurity in a world where our reliance on, and threats to, digital systems and data are escalating in tandem with a surging demand for graduates skilled in cybersecurity tools and techniques.

This critical position will sit within the School\'s Information Security Discipline whose research and teaching addresses a range of interdisciplinary topics in information security management, cryptography, network security and digital forensics. QUT is also one of the founding members of the newly-established Cyber Security Cooperative Research Centre. This position will involve conducting high quality research in emerging areas of cybersecurity; teaching undergraduate and postgraduate classes in cybersecurity principles and practices; and supervising higher-degree research students. The research will be conducted in one or more areas of cybersecurity principles and practices such as:

• Critical infrastructure design

• Computer security certification

• Identity management

• Digital forensics

• Network security

• Ransomware recovery

• Security auditing

• Information security management

• Trusted computing bases

• Malware analysis

• Intrusion detection

• Security-by-design

• Social engineering

• Applied cryptography

• Cloud security

• Supply chain security

Closing date for applications: 22 September 2018

More information: https://qut.nga.net.au/?jati=D9C23EA3-394E-7D62-5EDD-A474F0AE7BD7

Overview

Algorand is the next generation blockchain platform and digital currency. Possessing a thorough and thoughtfully constructed decentralized economy where all transactions are safe, fast and uncensored while scalable to billions of users, Algorand will help unleash the economic potential of people across the globe as we democratize access to financial instruments.

The Team

The Algorand team combines technological luminaries and proven business leaders. Algorand is founded by Silvio Micali, MIT Ford Professor of Engineering and recipient of the Turing Award in Computer Science.

Our office is located in the heart of downtown Boston. All positions are in this location, though remote work is possible for exceptional candidates.

The Role

This is a senior level role where you will have the opportunity to influence the design and implementation of Algorand’s core cryptographic protocols and schemes. You’ll be working closely with senior cryptographers at the company to engineer new schemes and constructions, implement and deploy them at scale. This involves open source development, contribution to cutting-edge research, and industry standards.

Cryptography engineers are expected to have deep domain knowledge, be familiar with the nuances of implementing public-key cryptography, side-channel attacks, padding oracles, constant-time implementations.

Responsibilities

You will join a small, extremely capable, and enthusiastic Boston-based team. Your ideas and your innovation will help shape the new blockchain and cryptocurrency ecosystem of tomorrow. The current suite of projects are implemented in primarily Go and C++.

The core product will be open sourced. Significant open source contribution experience will be considered very favorably.

Closing date for applications: 1 July 2019

Contact: Sergey Gorbunov, sergey (at) algorand.com

More information: https://www.algorand.com/careers/

The Faculty of Engineering, Computer and Mathematical Sciences at the University of Adelaide strives to develop a culture of high performance, collaboration and respect that attracts and nurtures exceptional talent to deliver excellence. We invite applications from suitably qualified women to join us as Associate Professor/Senior Lecturer in Cyber Security in our School of Computer Science to drive research with profound impact and to participate in our vibrant learning environment.

In the most recent Academic Ranking of World Universities (Computer Science & Engineering) the School of Computer Science was ranked 43rd world-wide. We can provide you with an excellent research and industry environment in cybersecurity in which to thrive. This continuing position is a great opportunity for you to set new research directions and contribute to teaching curriculum development.

A variety of flexible working arrangements are available for the successful candidate.

Closing date for applications: 9 September 2018

More information: http://careers.adelaide.edu.au/cw/en/job/499007/senior-lecturer-associate-professor-in-cyber-security-school-of-computer

The ISG is seeking to recruit a post-doctoral research assistant to work in the area of cryptography. The position is available now and will run until the end of 2021.

The PDRA will work alongside Martin Albrecht and other cryptographic researchers at Royal Holloway on topics in lattice-based cryptography. This post is part of the EU H2020 PROMETHEUS project (http://prometheuscrypt.gforge.inria.fr) for building privacy preserving systems from advanced lattice primitives. Our research focus within this project is on cryptanalysis and implementations, but applicants with a strong background in other areas such as protocol/primitive design are also encouraged to apply.

Applicants should have already completed, or be close to completing, a PhD in a relevant discipline. Applicants should have an outstanding research track record in cryptography. Applicants should be able to demonstrate scientific creativity, research independence, and the ability to communicate their ideas effectively in written and verbal form.

In return we offer a highly competitive rewards and benefits package including generous annual leave and training and development opportunities. This is a full time fixed term post is based in Egham, Surrey where the College is situated in a beautiful, leafy campus near to Windsor Great Park and within commuting distance from London.

To view further details of this post and to apply please visit https://jobs.royalholloway.ac.uk. For queries on the application process the Human Resources Department can be contacted by email at: recruitment (at) rhul.ac.uk.

Please quote the reference: 0818-334

Closing date for applications: 17 September 2018

Contact: Martin Albrecht, martin.albrecht _at_ royalholloway.ac.uk

More information: https://jobs.royalholloway.ac.uk/vacancy.aspx?ref=0818-334

The 2018 TCC Test-of-Time Award goes to Dan Boneh, Eu-Jin Goh and Kobbi Nissim, for their TCC 2005 paper "Evaluating 2-DNF Formulas on Ciphertexts".

The award committee recognizes this paper "for introducing compact two-operation homomorphic encryption and developing new bilinear map techniques that led to major improvements in the design of cryptographic schemes."

The TCC Test of Time Award recognizes outstanding papers, published in TCC at least eight years ago, making a significant contribution to the theory of cryptography, preferably with influence also in other area of cryptography, theory, and beyond. The inaugural TCC Test of Time Award was given in TCC 2015 for papers published no later than TCC 2007.

The Noise Protocol Framework, introduced recently, allows for the design and construction of secure channel protocols by describing them through a simple, restricted language from which complex key derivation and local state transitions are automatically inferred. Noise "Handshake Patterns" can support mutual authentication, forward secrecy, zero round-trip encryption, identity hiding and other advanced features. Since the framework's release, Noise-based protocols have been adopted by WhatsApp, WireGuard and other high-profile applications.

We present Noise Explorer, an online engine for designing, reasoning about and formally verifying arbitrary Noise Handshake Patterns. Based on our formal treatment of the Noise Protocol Framework, Noise Explorer can validate any Noise Handshake Pattern and then translate it into a model ready for automated verification. We use Noise Explorer to analyze 50 Noise Handshake Patterns. We confirm the stated security goals for 12 fundamental patterns and provide precise properties for the rest. We also analyze unsafe Noise patterns and discover potential attacks. All of this work is consolidated into a usable online tool that presents a compendium of results and can parse formal verification results to generate detailed-but-pedagogical reports regarding the exact security guarantees of each message of a Noise Handshake Pattern with respect to each party, under an active attacker and including malicious principals. Noise Explorer evolves alongside the standard Noise Protocol Framework, having already contributed new security goal verification results and stronger definitions for pattern validation and security parameters.

Symbolic methods have been used extensively for proving security of cryptographic protocols in the Dolev-Yao model, and more recently for proving security of cryptographic primitives and constructions in the computational model. However, existing methods for proving security of cryptographic constructions in the computational model often require significant expertise and interaction, or are fairly limited in scope and expressivity.

This paper introduces a symbolic approach for proving security of cryptographic constructions based on the Learning With Errors assumption (Regev, STOC 2005). Such constructions are instances of lattice-based cryptography and are extremely important due to their potential role in post-quantum cryptography. Following (Barthe, Gr\'egoire and Schmidt, CCS 2015), our approach combines a computational logic and deducibility problems---a standard tool for representing the adversary's knowledge, the Dolev-Yao model. The computational logic is used to capture (indistinguishability-based) security notions and drive the security proofs whereas deducibility problems are used as side-conditions to control that rules of the logic are applied correctly. We then use \AutoLWE, an implementation of the logic, to deliver very short or even automatic proofs of several emblematic constructions, including CPA-PKE (Gentry et al., STOC 2008), (Hierarchical) Identity-Based Encryption (Agrawal et al. Eurocrypt 2010), Inner Product Encryption (Agrawal et al. Asiacrypt 2011), CCA-PKE (Micciancio et al., Eurocrypt 2012). The main technical novelty beyond AutoLWE is a set of (semi-)decision procedures for deducibility problems, using extensions of Gr\"obner basis computations for subalgebras in the (non-)commutative setting (instead of ideals in the commutative setting). Our procedures cover the theory of matrices, which is required for lattice-based assumption, as well as the theory of non-commutative rings, fields, and Diffie-Hellman exponentiation, in its standard, bilinear and multilinear forms. Additionally, AutoLWE supports oracle-relative assumptions, which are used specifically to apply (advanced forms of) the Leftover Hash Lemma, an information-theoretical tool widely used in lattice-based proofs.

Post-quantum cryptosystems involve basically the families of algorithms based on lattices, error correcting codes, multivariate quadratic systems (MQ), and schemes based on symmetric cryptography primitives in general, as well as on hash functions. The project in which the candidate will be inserted aims to specify, develop and analyze secure and hardware-friendly post-quantum cryptographic schemes for providing a variety of security services, including encryption, authentication and digital signatures.

The focus will be on performance improvements, possibly in terms of processing time and energy requirements, but especially in terms of key, signatures and ciphertext sizes. The security analysis of these schemes should consider both cryptanalytic attacks and implementation-related threats, such as side-channel attacks. The performance evaluation of the schemes will be both theoretical (considering computational complexity, underlying parallelism opportunities) and experimental (using software prototypes and hardware implementations).

The main requirements for the application are: (1) to have a solid background in cryptography, preferably (but not necessarily) with post-quantum primitives; (2) to have good design/programming skills, preferably (but not necessarily) in programming languages such as C and/or hardware description languages such as VHDL, and (3) to be enrolled (or to be willing to enroll) at the Graduate Program in Electrical Engineering, Escola Politécnica, Universidade de São Paulo, São Paulo campus (http://ppgee.poli.usp.br/en/), with a full time dedication.

This opportunity is open for candidates of any nationality.

Closing date for applications: 27 August 2018

Contact: Prof. Marcos A. Simplicio Jr -- msimplicio (at) larc.usp.br

Are You Interested in Cryptography And/Or Blockchain Technology?

Post-Doc Positions.

Professor Ivan Visconti is the scientific coordinator for University of Salerno of the project Privacy-Enhancing Cryptography in Distributed Ledgers (PRIViLEDGE) and is involved in several other research activities related to Cybersecurity, Cryptography and Blockchain Technology. Expressions of interest for post-doc positions in the field of privacy-preserving cryptography and distributed ledger technology, to be supervised by professor Ivan Visconti are welcome. Candidates are expected to have a solid publication record (e.g., IACR conferences, CCS, IEEE S&P,....). The positions are available immediately. The net salary can be even higher than the average net salary of an associate professor in Italy. There is also some travel budget to attend conferences, project meetings and research visits. In case you are interested, please send your CV and 2 names for letters of reference to Ivan Visconti (ivan DOT visconti AT gmail DOT com).

PhD Positions.

There are up to 14 PhD positions at the computer engineering department of University of Salerno (Italy). The deadline for applications is September 19, 2018, and the master degree must be obtained by November 6, 2018.

Closing date for applications: 6 November 2018

Contact: Ivan Visconti (ivan DOT visconti AT gmail DOT com)

More information: https://goo.gl/DmFgGM

When designing a new symmetric-key primitive, the designer must show resistance to know attacks. Perhaps most prominent amongst these are linear and differential cryptanalysis. However, it is notoriously difficult to accurately demonstrate e.g. a block cipher's resistance to these attacks, and thus most designer resort to deriving bounds on the linear correlations and differential probabilities of their cipher. On the other side of the spectrum, the cryptanalyst is also interested in accurately assessing the strength of a linear or differential attack.

While several tools have been developed to search for optimal linear and differential trails, e.g. MILP and SAT based methods, only few approaches specifically try to find as many trails of a single approximation or differential as possible. This can result in an overestimate of a ciphers resistance to linear and differential attacks, as was for example the case for PRESENT.

In this work, we present a new algorithm for linear and differential trail search. The algorithm represents the problem of estimating approximations and differentials as the problem of finding many paths through a multistage graph, and we demonstrate that this approach allows is to find a very large number of trails for each approximation or differential. Moreover, we show how the algorithm can be used to efficiently estimate the key dependent correlation distribution of a linear approximation, facilitating advanced linear attacks. We apply the algorithm to 17 different ciphers, and demonstrate new and improved results on several of these.

A new approach to invariant subspaces and nonlinear invariants is developed. This results in both theoretical insights and practical attacks on block ciphers. It is shown that, with minor modifications to some of the round constants, Midori-64 has a nonlinear invariant with $2^{96}$ corresponding weak keys. Furthermore, this invariant corresponds to a linear hull with maximal correlation. By combining the new invariant with integral cryptanalysis, a practical key-recovery attack on 10 rounds of unmodified Midori-64 is obtained. The attack works for $2^{96}$ weak keys and irrespective of the choice of round constants. The data complexity is $1.25 \cdot 2^{21}$ chosen plaintexts and the computational cost is dominated by $2^{56}$ block cipher calls. Finally, it is shown that similar techniques lead to a practical key-recovery attack on MANTIS-4. The full key is recovered using 640 chosen plaintexts and the attack requires about $2^{56}$ block cipher calls.

Protocols for secure multiparty computation (MPC) enable a set of mutually distrusting parties to compute an arbitrary function of their inputs while preserving basic security properties like \emph{privacy} and \emph{correctness}. The study of MPC was initiated in the 1980s where it was shown that any function can be securely computed, thus demonstrating the power of this notion. However, these proofs of feasibility were theoretical in nature and it is only recently that MPC protocols started to become efficient enough for use in practice. Today, we have protocols that can carry out large and complex computations in very reasonable time (and can even be very fast, depending on the computation and the setting). Despite this amazing progress, there is still a major obstacle to the adoption and use of MPC due to the huge expertise needed to design a specific MPC execution. In particular, the function to be computed needs to be represented as an appropriate Boolean or arithmetic circuit, and this requires very specific expertise. In order to overcome this, there has been considerable work on compilation of code to (typically) Boolean circuits. One work in this direction takes a different approach, and this is the SPDZ compiler (not to be confused with the SPDZ protocol) that takes high-level Python code and provides an MPC run-time environment for securely executing that code. The SPDZ compiler can deal with arithmetic and non-arithmetic operations and is extremely powerful. However, until now, the SPDZ compiler could only be used for the specific SPDZ family of protocols, making its general applicability and usefulness very limited.

In this paper, we extend the SPDZ compiler so that it can work with general underlying protocols. Our SPDZ extensions were made in mind to enable the use of SPDZ for arbitrary protocols and to make it easy for others to integrate existing and new protocols. We integrated three different types of protocols, an honest-majority protocol for computing arithmetic circuits over a field (for any number of parties), a three-party honest majority protocol for computing arithmetic circuits over the ring of integers $\Z_{2^n}$, and the multiparty BMR protocol for computing Boolean circuits. We show that a single high-level SPDZ-Python program can be executed using all of these underlying protocols (as well as the original SPDZ protocol), thereby making SPDZ a true general run-time MPC environment.

In order to be able to handle both arithmetic and non-arithmetic operations, the SPDZ compiler relies on conversions from field elements to bits and back. However, these conversions do not apply to ring elements (in particular, they require element division), and we therefore introduce new bit decomposition and recomposition protocols for the ring over integers with replicated secret sharing. These conversions are of independent interest and utilize the structure of $\Z_{2^n}$ (which is much more amenable to bit decomposition than prime-order fields), and are thus much more efficient than all previous methods.

We demonstrate our compiler extensions by running a complex SQL query and a decision tree evaluation over all protocols.

In 2005, Yen et al. proposed the first $N-1$ attack on the modular exponentiation algorithms such as BRIP and square-and-multiply-always methods. This attack makes use of the ciphertext $N-1$ as a distinguisher to obtain a strong relation between side-channel leakages and secret exponent. The so-called $N-1$ attack is one of the most important attacks, as it requires a non-adaptive chosen ciphertext which is considered as a more realistic attack model compared to adaptive chosen ciphertext scenario. To protect the implementation against $N-1$ attack, several literatures propose the simplest solution, i.e. \textquotedblleft block the special message $N-1$". In this paper, we conduct an in-depth research on the $N-1$ attack based on the square-and-multiply-always (SMA) and Montgomery Ladder (ML) algorithms. We show that despite the unaccepted ciphertext $N-1$ countermeasure, other types of $N-1$ attacks is applicable to specific classes of Elgamal cryptosystems. We propose new chosen-message power-analysis attacks which utilize a chosen ciphertext $c$ such that $c^2= -1 \bmod p$ where $p$ is the prime number used as a modulus in Elgamal. Such a ciphertext can be found simply when $p\equiv 1\mod 4$. We demonstrate that ML and SMA algorithms are subjected to our new $N-1$-type attack by utilizing a different ciphertext. We implement the proposed attacks on the TARGET Board of the ChipWhisperer CW1173 and our experiments validate the feasibility and effectiveness of the attacks by using only a single power trace.

In this paper, we study the authenticated key exchange (AKE) based on supersingular isogeny problems which are believed to be difficult for quantum computers. We first propose a three-pass AKE based on 1-Oracle SIDH assumption whose soundness is guaranteed by a strictly limited gap problem. To enhance the soundness, we propose a two-pass AKE based on standard SIDH assumption. The three-pass AKE achieves about 20\% speedup compared with the SIDH variant of FSXY scheme and narrows the bandwidth by approximately 49.3\% without lose of security. And the two-pass scheme narrows the bandwidth by around 23\% and yields a factor 12\% acceleration than the SIDH variant of FSXY scheme.

In the random oracle model, both three-pass AKE and two-pass AKE protocols are secure in the CK model, supporting arbitrary registration of public key, and resistant to the weak perfect forward secrecy (wPFS) attack, key-compromise impersonation (KCI) attack and maximal exposure (MEX) attack, which solves the open problem provided Galbraith of looking for new techniques to design and prove security of AKE in SIDH setting with the widest possible adversarial goals.

We study a simulation paradigm, referred to as local simulation, in garbling schemes. This paradigm captures simulation proof strategies in which the simulator consists of many local simulators that generate different blocks of the garbled circuit. A useful property of such a simulation strategy is that only a few of these local simulators depend on the input, whereas the rest of the local simulators only depend on the circuit.

We formalize this notion by defining locally simulatable garbling schemes. By suitably realizing this notion, we give a new construction of succinct garbling schemes for Turing machines assuming the polynomial hardness of compact functional encryption and standard assumptions (such as either CDH or LWE). Prior constructions of succinct garbling schemes either assumed sub-exponential hardness of compact functional encryption or were designed only for small-space Turing machines.

We also show that a variant of locally simulatable garbling schemes can be used to generically obtain adaptively secure garbling schemes for circuits. All prior constructions of adaptively secure garbling that use somewhere equivocal encryption can be seen as instantiations of our construction.

This work describes a common framework for scale-invariant families of fully homomorphic schemes based on Ring-LWE, unifying the plaintext space and the noise representation. This new formalization allows to build bridges between B/FV, HEAAN and TFHE and provides the possibility to take advantage of the best of these three schemes. In particular, we review how different strategies developed for each of these schemes, such as bootstrapping, external product, integer arithmetic and Fourier series, can be combined to evaluate the principle nonlinear functions involved in convolutional neural networks. Finally, we show that neural networks are particularly robust against perturbations that could potentially result from the propagation of large homomorphic noise. This allows choosing smaller and more performant parameters sets.

Cryptography is a key element in establishing trust and enabling services in the digital world. Currently, cryptography is realized with mathematical operations and represented in ways that are not accessible to human users. Thus, humans are left out of the loop when establishing trust and security in the digital world. In many areas the interaction between users and machines is being made more and more seamless and user-friendly, but cryptography has not really enjoyed such development. In this paper, we present ideas that could make cryptography more accessible to humans. We review previous research on this topic and some results that have been achieved. We propose several topics and problems that need to be solved in order to build cryptography for human senses. These measures range from practical implementations of existing methods and utilising a wider range of human senses all the way to building the theoretical foundations of this new form of cryptography.

We describe obfuscation schemes for matrix-product branching programs that are purely algebraic and employ matrix algebra and tensor algebra over a finite field. In contrast to the obfuscation schemes of Garg et al (SICOM 2016) which were based on multilinear maps, these schemes do not use noisy encodings. We prove that there is no efficient attack on our scheme based on re-linearization techniques of Kipnis-Shamir (CRYPTO 99) and its generalization called XL-methodology (Courtois et al, EC2000). We also provide analysis to claim that general Grobner-basis computation attacks will be inefficient. In a generic colored matrix model our construction leads to a virtual-black-box obfuscator for NC$^1$ circuits.

Security against selective opening attack (SOA) for receivers requires that in a multi-user setting, even if an adversary has access to all ciphertexts, and adaptively corrupts some fraction of the users to obtain the decryption keys corresponding to some of the ciphertexts, the remaining (potentially related) ciphertexts retain their privacy. In this paper, we study simulation-based selective opening security for receivers of public key encryption (PKE) schemes under chosen-ciphertext attacks (RSIM-SO-CCA).

Concretely, we first show that some known PKE schemes meet RSIM-SO-CCA security. Then, we introduce the notion of master-key SOA security for identity-based encryption (IBE), and extend the Canetti-Halevi-Katz (CHK) transformation to show generic PKE constructions achieving RSIM-SO-CCA security. Finally, we show how to construct an IBE scheme achieving master-key SOA security.

Consensus (a.k.a. Byzantine agreement) is arguably one of the most fundamental problems in distributed systems, playing also an important role in the area of cryptographic protocols as the enabler of a (secure) broadcast functionality. While the problem has a long and rich history and has been analyzed from many different perspectives, recently, with the advent of blockchain protocols like Bitcoin, it has experienced renewed interest from a much wider community of researchers and has seen its application expand to various novel settings.

One of the main issues in consensus research is the many different variants of the problem that exist as well as the various ways the problem behaves when different setup, computational assumptions and network models are considered. In this work we perform a systematization of knowledge in the landscape of consensus research starting with the original formulation in the early 1980s up to the present blockchain-based new class of consensus protocols. Our work is a roadmap for studying the consensus problem under its many guises, classifying the way it operates in many settings and highlighting the exciting new applications that have emerged in the blockchain era.