International Association
for Cryptologic Research

Attribute-based encryption (ABE) enables limiting access to encrypted data to users with certain attributes. Different aspects of ABE were studied, such as the multi-authority setting (MA-ABE), and policy hiding, meaning the access policy is unknown to unauthorized parties. However, no practical scheme so far provably provides both properties, which are often desirable in real-world applications: supporting decentralization, while hiding the access policy. We present the first practical decentralized ABE scheme with a proof of being policy-hiding. Our construction is based on a decentralized inner-product predicate encryption scheme, introduced in this paper, which hides the encryption policy. It results in an ABE scheme supporting conjunctions, disjunctions and threshold policies, that protects the access policy from parties that are not authorized to decrypt the content. Further, we address the issue of receiver privacy. By using our scheme in combination with vector commitments, we hide the overall set of attributes possessed by the receiver from individual authorities, only revealing the attribute that the authority is controlling. Finally, we propose randomizing-polynomial encodings that immunize the scheme in the presence of corrupt authorities.

We consider a situation in which two mutually distrusting parties, each possessing a secret piece of information, wish to exchange these secrets while communicating over a secure channel, in effect ``trading" them. Each is afraid of counterparty risk: Alice fears that as soon as she sends her secret to Bob he will cease communication without sending his secret in return, and likewise for the reverse case. In the situation where Alice and Bob's secrets are protected by isogenies, we propose a system in which Alice and Bob may fairly exchange their secrets without counterparty risk, and without a trusted third party. We then discuss potential applications.

Protocols for secure multiparty computation enable a set of parties to compute a joint function of their inputs, while preserving \emph{privacy}, \emph{correctness} and more. In theory, secure computation has broad applicability and can be used to solve many of the modern concerns around utilization of data and privacy. Huge steps have been made towards this vision in the past few years, and we now have protocols that can carry out large computations extremely efficiently, especially in the setting of an honest majority. However, in practice, there are still major barriers to widely deploying secure computation, especially in a decentralized manner.

In this paper, we present the first end-to-end automated system for deploying large-scale MPC protocols between end users, called MPSaaS (for \textit{MPC system-as-a-service}). Our system enables parties to pre-enroll in an upcoming MPC computation, and then participate by either running software on a VM instance (e.g., in Amazon), or by running the protocol on a mobile app, in Javascript in their browser, or even on an IoT device. Our system includes an automation system for deploying MPC protocols, an administration component for setting up an MPC computation and inviting participants, and an end-user component for running the MPC protocol in realistic end-user environments. We demonstrate our system for a specific application of running secure polls and surveys, where the secure computation is run end-to-end with each party actually running the protocol (i.e., without relying on a set of servers to run the protocol for them). This is the first such system constructed, and is a big step forward to the goal of commoditizing MPC.

One of the cryptographic difficulties that arise in this type of setting is due to the fact that end users may have low bandwidth connections, making it a challenge to run an MPC protocol with high bandwidth. We therefore present a protocol based on Beerliova-Trubiniova and Hirt (TCC 2008) with many optimizations, that has very low concrete communication, and the lowest published for small fields. Our protocol is secure as long as less than a third of the parties are \textit{malicious}, and is well suited for computing both arithmetic and Boolean circuits. We call our protocol HyperMPC and show that it has impressive performance. In particular, 150 parties can compute statistics---mean, standard deviation and regression---on 4,000,000 inputs (with a circuit of size 16,000,000 gates of which 6,000,000 are multiplication) in five minutes, and 10 parties can compute the same circuit in 30 seconds. Although our end-to-end system can be used to run any MPC protocol (and we have incorporated numerous protocols already), we demonstrate it for our new protocol that is optimized for end-users without high bandwidth.

The Computer Science Department at National Chengchi University invites applications for multiple tenure-track/tenured faculties from outstanding candidates at all ranks (assistant, associate, and full professor) to begin at Spring 2019 or Fall 2019.

Initial review of applications will begin on October 1st, 2018 and continue until the position is filled. The position may close when an adequate number of qualified applications are received.

We seek candidates in research areas related to all fields in Computer Science. Candidates from the following research areas are especially welcome:

• Artificial Intelligence

• Information Security

• Interdisciplinary fields of computer science and social science (eg., CS and Digital Content, CS and Communication, CS and Finance, etc. )

At a minimum, candidates must have a Ph.D. degree in Computer Science or a closely related field and have demonstrated strong research ability.

Applicants must send curriculum vitae, transcripts, diploma certificate, a copy of Ph.D. dissertation or abstract, recent publications, and at least two recommendation letters to recruit (at) cs.nccu.edu.tw or

Faculty Recruit Committee Department of Computer Science

National Chengchi University

64, Sec. 2, ZhiNan Rd. Wenshan District

Taipei, Taiwan, 11605

R.O.C.

Applicants are invited to visit our web page at https://www.cs.nccu.edu.tw .

Closing date for applications: 1 February 2019

Contact: Raylin Tso

Chairman of the Department of Computer Science, National Chengchi University

eMail: raylin (at) cs.nccu.edu.tw

More information: https://www.cs.nccu.edu.tw

InfoSec GLobal(ISG) secures data and communications for critical systems and IoT devices. Our Cryptographic Life-Cycle Management delivers a platform that provides threat management, enables crypto agility and creates a path to quantum safe. We are looking for a Security Engineer who will be responsible for

• Implementation of cryptographic primitives (optimizations, countermeasures)

• Implementation of security protocols

• Side-channel analysis of implementations

• C programming proficiency

• Applied research in cryptography and security

• Patent and standards development

You have a Master in Computer Science with 5 years of experience in Security Engineering or a PhD in Computer Science with a focus on Security and a profound knowledge in cryptography and embedded devices

Skills:

• Software development in C and Java

• Development on embedded devices

• Experience with development on Android and iOS

• Experience with ARM processors

• Experience with side-channel analysis and attacks

• Experience with implementation of cryptographic primitives

• Experience with Latex

• Experience with applied research

Closing date for applications: 19 October 2018

Contact: Jennifer Quaid

ISG

jennifer.quaid (at) infosecglobal.com

InfoSec Global (ISG) is a next-generation cryptography company that secures data and communications for critical systems and IoT devices. ISG’s Cryptographic Life-Cycle Management delivers a platform that provides threat management, enables crypto agility and creates a path to quantum safe. We are looking for a Post Quantum Cryptography Expert who will be responsible for:

• Writing and publishing and public speaking

• Prototyping, proof of concept development

• Consultancy in the field of asymmetric cryptography

• Applied research in post quantum cryptography

• Patent and standards development

Education Required:

• PhD in Cryptography

• Profound knowledge in cryptography

• Profound knowledge in lattice-based cryptography

• Profound knowledge in code-based cryptography

• Profound knowledge in isogeny-based cryptography

Skills:

• Software development in C, Java or Python

• Experience with implementation of cryptographic primitives

• Experience with development on Windows, Linux, Android and iOS

• Experience with Latex

• Experience with applied research

Closing date for applications: 31 October 2018

Contact: Jennifer Quaid

InfoSec Global

jennifer.quaid (at) infosecglobal.com

InfoSec Global (ISG) is a next-generation cryptography company that secures data and communications for critical systems and IoT devices. ISG’s Cryptographic Life-Cycle Management delivers a platform that provides threat management, enables crypto agility and creates a path to quantum safe. We are looking for a Security Architect who will be responsible for:

• Writing and publishing and public speaking

• Design and analysis of IT security systems

• Prototype, proof of concept development

• Consultancy in the field of secure systems

• Applied research in cryptography and security

• Patent and standards development

Education and Experience: You have a Master in Computer Science with 5 years of experience in Security Engineering or a PhD in Computer Science with focus on Security, and a profound knowledge in cryptography, network security, systems engineering, security design, cloud security and security protocols.

Skills: Software development in C, Java and Python, Experience with security in Windows, Linux, Android and iOS, Experience with cloud infrastructure, Experience with IoT environment, Experience with Latex, Experience with applied research

Closing date for applications: 31 October 2018

Contact: Jennifer Quaid

InfoSec Global

jennifer.quaid (at) infosecglobal.com

Event date: 11 March to 12 March 2019
Submission deadline: 17 December 2018
Notification: 15 January 2019

Goyal and Kumar (STOC'18) recently introduced the notion of non-malleable secret sharing. Very roughly, the guarantee they seek is the following: the adversary may potentially tamper with all of the shares, and still, either the reconstruction procedure outputs the original secret, or, the original secret is ``destroyed" and the reconstruction outputs a string which is completely ``unrelated" to the original secret. Prior works on non-malleable codes in the 2 split-state model imply constructions which can be seen as 2-out-of-2 non-malleable secret sharing (NMSS) schemes. Goyal and Kumar proposed constructions of t-out-of-n NMSS schemes. These constructions have already been shown to have a number of applications in cryptography.

We continue this line of research and construct NMSS for more general access structures. We give a generic compiler that converts any statistical (resp. computational) secret sharing scheme realizing any access structure into another statistical (resp. computational) secret sharing scheme that not only realizes the same access structure but also ensures statistical non-malleability against a computationally unbounded adversary who tampers each of the shares arbitrarily and independently. Instantiating with known schemes we get unconditional NMMS schemes that realize any access structures generated by polynomial size monotone span programs. Similarly, we also obtain conditional NMMS schemes realizing access structure in monotoneP (resp. monotoneNP) assuming one-way functions (resp. witness encryption).

Towards considering more general tampering models, we also propose a construction of n-out-of-n NMSS. Our construction is secure even if the adversary could divide the shares into any two (possibly overlapping) subsets and then arbitrarily tamper the shares in each subset. Our construction is based on a property of inner product and an observation that the inner-product based construction of Aggarwal, Dodis and Lovett (STOC'14) is in fact secure against a tampering class that is stronger than 2 split-states. We also show applications of our construction to the problem of non-malleable message transmission.

This work provides a systematic analysis of primality testing under adversarial conditions, where the numbers being tested for primality are not generated randomly, but instead provided by a possibly malicious party. Such a situation can arise in secure messaging protocols where a server supplies Diffie-Hellman parameters to the peers, or in a secure communications protocol like TLS where a developer can insert such a number to be able to later passively spy on client-server data. We study a broad range of cryptographic libraries and assess their performance in this adversarial setting. As examples of our findings, we are able to construct 2048-bit composites that are declared prime with probability \(1/16\) by OpenSSL's primality testing in its default configuration; the advertised performance is \(2^{-80}\). We can also construct 1024-bit composites that always pass the primality testing routine in GNU GMP when configured with the recommended minimum number of rounds. And, for a number of libraries (Cryptlib, LibTomCrypt, JavaScript Big Number, WolfSSL), we can construct composites that always pass the supplied primality tests. We explore the implications of these security failures in applications, focusing on the construction of malicious Diffie-Hellman parameters. We show that, unless careful primality testing is performed, an adversary can supply parameters $(p,q,g)$ which on the surface look secure, but where the discrete logarithm problem in the subgroup of order $q$ generated by $g$ is easy. We close by making recommendations for users and developers. In particular, we promote the Baillie-PSW primality test which is both efficient and conjectured to be robust even in the adversarial setting for numbers up to a few thousand bits.

Cloud storage services use deduplication for saving bandwidth and storage. An adversary can exploit side-channel information in several attack scenarios when deduplication takes place at the client side, leaking information on whether a specific plaintext exists in the cloud storage. Generalising existing security definitions, we introduce formal security games for a number of possible adversaries in this domain, and show that games representing all natural adversarial behaviors are in fact equivalent. These results allow users and practitioners alike to accurately assess the vulnerability of deployed systems to this real-world concern.

Today, about 10% of TLS connections are still using CBC-mode cipher suites, despite a long history of attacks and the availability of better options (e.g. AES-GCM). In this work, we present three new types of attack against four popular fully patched implementations of TLS (Amazon's s2n, GnuTLS, mbed TLS and wolfSSL) which elected to use ``pseudo constant time'' countermeasures against the Lucky 13 attack on CBC-mode. Our attacks combine several variants of the PRIME+PROBE cache timing technique with a new extension of the original Lucky 13 attack. They apply in a cross-VM attack setting and are capable of recovering most of the plaintext whilst requiring only a moderate number of TLS connections. Along the way, we uncovered additional serious (but easy to patch) bugs in all four of the TLS implementations that we studied; in three cases, these bugs lead to Lucky 13 style attacks that can be mounted remotely with no access to a shared cache. Our work shows that adopting pseudo constant time countermeasures is not sufficient to attain real security in TLS implementations in CBC mode.

Secret sharing is a fundamental cryptographic primitive. One of the main goals of secret sharing is to share a long secret using small shares. In this paper we consider a family of statistical secret sharing schemes indexed by N, the number of players. The family is associated with a pair of relative thresholds tau and kappa, that for a given N, specify a secret sharing scheme with privacy and reconstruction thresholds, N tau and N kappa, respectively. These are non-perfect schemes with gap N(kappa-tau) and statistical schemes with errors epsilon(N) and delta(N) for privacy and reconstruction, respectively. We give two constructions of secret sharing families as defined above, with security against (i) an adaptive, and (ii) a non-adaptive adversary, respectively. Both constructions are modular and use two components, an invertible extractor and a stochastic code, and surprisingly in both cases, for any kappa>tau, give explicit families for sharing a secret that is a constant fraction (in bits) of N, using binary shares. We show that the construction for non-adaptive adversary is optimal in the sense that it asymptotically achieves the upper bound N(kappa-tau) on the secret length. We relate our results to known works and discuss open questions.

Low Entropy Masking Scheme (LEMS) has attracted wide attention for its low-cost feature of small fixed mask sets in Side-Channel-Analysis (SCA). To achieve the expected side channel security, it is necessary to find a balanced mask set to reduce the correlations between key dependent variables and their corresponding leakages. However, the security proof of LEMS, based on an inadequate assumption, might lead to consequent mask sets proposed without balance property, which could cause vulnerable LEMS implementations. This paper focusing on correcting and improving this scheme, first gives the formal definitions of univariate balance property on mask sets and extends it to multivariate settings. From these definitions, we propose three fundamental properties to analyze the balance of mask sets in Rotating Sbox Masking (RSM), the most popular LEMS implementations. To demonstrate the definitions and properties, three state-of-the-art RSM mask sets were selected as research objects. The corresponding attacks when any properties violated distinctly indicate the necessity of evaluating the balance property of the mask set in advance (during the design phase). However, it is found impossible to get a mask set for the RSM with all three properties satisfied, which means the vulnerabilities of RSM scheme in its unbalanced mask set are unavoidable. Thus, this promising masking scheme may be broken for its unqualified mask set.

Event date: 7 February to 9 February 2019
Submission deadline: 15 September 2018
Notification: 25 October 2018

Event date: 4 June to 7 June 2019
Submission deadline: 18 February 2019
Notification: 8 April 2019

Applications are invited for several Research fellow or senior research fellow positions at the National Satellite of Excellence on Trustworthy Systems at the National University of Singapore. Applicants should have a PhD in Computer Science or related discipline with research focus on security, or programming languages, or embedded systems. Please email your CV to abhik (at) comp.nus.edu.sg for inquiries.

Closing date for applications: 30 June 2019

Contact: Prof. Abhik Roychoudhury

School of Computing

National University of Singapore

abhik (at) comp.nus.edu.sg

More information: https://www.comp.nus.edu.sg/~abhik

We are looking for a PostDoc to research on topics related theory and practice of functional encryption, including

* pairing-based

* lattice-based

* black-box (im)possibility results

and applications to Internet of Things and Blockchain. Research is conducted within the EU H2020 Functional Encryption Technology (FENTEC) project in conjunction with the academic partners Edinburg University, ENS Paris, Flensburg University, Helsinki University, KU Leuven and the industrial partners ATOS, Kudelski Group (former Nagravision), WALLIX and XLAB.

The position includes

* competitive salary

* travel budget (conference, project meetings, research visits)

* team of 1-2 PhDs

* academic freedom to create own research profile

* (optional) teaching opportunity

Please send your CV to The Chancelor, Mrs. Sabine Christiansen at personal.bewerbungen(at)hs-flensburg.de.

Closing date for applications: 1 September 2018

Contact: Prof. Dr. Sebastian Gajek, Head of the IT-Security and Cryptography group (ITSC), Web: https://www.itsc.inf.hs-flensburg.de, Email: sebastian.gajek(at)hs-flensburg.de

More information: https://hs-flensburg.de/node/3893

Simula UiB has open positions for senior researchers in cryptography.

About us: Simula UiB is a research organization located in Bergen, Norway. We currently employ 17 people researching cryptography and information theory and supervising master and Ph.D. students. Due to increased base funding from the Norwegian government, we are now looking to expand our activity and hire two senior researchers in permanent positions.

What we want: We are looking for someone who is an active researcher in cryptography, with an excellent publication record. The successful candidate is expected to attract and supervise students. We envision the ideal candidate to be someone who has 10–15 years of experience since obtaining his/her Ph.D. degree. Candidates with less experience should also apply.

What we offer:

Competitive salary and a fast hiring process.

Two Ph.D. positions and one postdoc position are associated with each researcher.

Funding for travel and hosting visitors.

A good working environment in modern offices located centrally in Bergen.

Closing date for applications:

Contact: Website: www.simula-uib.com

If you want to learn more about this opportunity please email Kjell Jørgen Hole (CEO) at hole (at) simula.no, Håvard Raddum (leader of the crypto section) at haavardr (at) simula.no or Øyvind Ytrehus (chief scientist) at oyvindy (at) simula.no.

This is an urgent call for interested applicants. A funded Ph.D. student position is available starting January 2019 (all documents submitted by Sep. 15th, 2018 for International students) to work on different aspects of Cryptographic Engineering in the CSE department with Dr. Mehran Mozaffari Kermani (CSE department of University of South Florida, Tampa, FL).

The required expertise includes:

- Master’s in Computer Engineering or Electrical Engineering

- Solid background in digital design, VLSI, computer arithmetic, and ASIC/FPGA implementations

- Solid HDL expertise

- Outstanding English (if English tests are taken) to be eligible for department funding

- Motivation to work beyond the expectations from an average Ph.D. student and publish in top tier venues

Please closely observe the admission requirement details before emailing,

We are looking for motivated, talented, and hardworking applicants who have background and are interested in working on different aspects of Cryptographic Engineering with emphasis on:

- Cryptographic hardware systems

- Side-channel attacks, particularly fault and power analysis attacks

Please send me your updated CV (including list of publications, language test marks, and references), transcripts for B.Sc. (and/or M.Sc.), and a statement of interest to mehran2 (at) usf.edu as soon as possible.

NOTE: At this time, I consider only the applicants who have already taken TOEFL/IELTS and GRE exams with excellent marks. The successful candidate will be asked to apply formally very soon to the department, so all the material has to be ready.

Mehran Mozaffari Kermani

Closing date for applications: 30 November 2018

More information: http://www.csee.usf.edu/~mehran2/