IACR News
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12 December 2017
Aner Ben-Efraim
We first extend free addition and multiplication by a constant to the multiparty setting. We further extend to the multiparty setting efficient garbled multiplication gates. The garbled multiplication gate construction we show was previously achieved only in the two-party setting and assuming a random oracle.
Our main technical contribution is in garbling selector gates. Selector gates compute a simple ``if statement" in the arithmetic setting: the gate selects the output value from two input values in $\mathbb{F}_p$, according to a Boolean selector bit; if the bit is $0$ the output equals the value on the first wire, and if the bit is $1$ the output equals the value on the second wire. We show a new and designated garbled selector gate that reduces by approximately $33\%$ the evaluation time from the best previously known constructions that use existing techniques.
On the downside, we find that testing equality and computing exponentiation by a constant are significantly more complex to garble in the multiparty setting than in the two-party setting.
Jintai Ding, Scott Fluhrer, Saraswathy RV
11 December 2017
University of Bristol, Cryptography and Information Security group
Applications are invited for two Post-Doctoral Research Associate posts, hosted in the Cryptography and Information Security group [1] set within the University of Bristol; the group is recognised by EPSRC/NCSC as a UK Academic Centre of Excellence in Cyber Security Research (ACE-CSR).
These posts represent an exciting opportunity to join the group as part of the 5-year SCARV [2] project, in turn part of the recently announced, EPSRC/NCSC-supported Research Institute in Hardware Security & Embedded Systems (RISE) [3]. SCARV is a project focused on challenges in cryptographic engineering, at the intersection of computer architecture and cryptography: alongside both industrial (i.e., Cerberus Security Labs. and Thales) and academic partners, it aims to deliver more efficient, more secure platforms based on and around RISC-V. Given the project goals, a strong background in micro-processor design and implementation, and/or implementation (e.g., side-channel) attacks on cryptography is therefore desirable.
Although you will have at least a first degree and preferably a PhD in Computer Science, Electrical Engineering, or closely related discipline, we view relevant industrial experience as extremely valuable and therefore equally encourage applicants of this type.
- [1] http://www.bris.ac.uk/engineering/research/cryptography
- [2] http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef=EP/R012288/1
- [3] http://www.ukrise.org
Closing date for applications: 21 January 2018
Contact: Dr. Daniel Page (Daniel.Page (at) bristol.ac.uk)
More information: http://www.bris.ac.uk/jobs/find/details.html?nPostingID=6948&nPostingTargetID=42514&JobNum=ACAD103055
10 December 2017
The IACR sponsors a small number of Cryptology Schools providing intensive training on clearly identified topics in cryptology. The aim is to develop awareness and increased capacity for research in cryptology. A list of past and upcoming schools can be found at https://www.iacr.org/schools
Sutomore , Montenegro, 4 April - 5 April 2018
Submission deadline: 15 January 2018
Notification: 1 February 2018
Aarhus, Denmark, 28 May - 31 May 2018
Submission deadline: 1 February 2018
Notification: 1 March 2018
08 December 2017
University of Luxembourg
The successful candidate will join the APSIA group led by Prof. Peter Y. A. Ryan. The candidate will be part of the Luxembourg National Research Fund (FNR) project “Stateful Zero-Knowledge”, which will start on 1st March 2018 and will conduct pioneering research on zero-knowledge proofs. The candidate will be supervised by Prof. Peter Y. A. Ryan and by Dr. Alfredo Rial. The candidate’s tasks include the following:
- Conducting research on the following topics: zero-knowledge proofs and zero-knowledge data structures, privacy-preserving cryptographic protocols, universal composability and related security frameworks, design and implementation of a zero-knowledge compiler
- Providing guidance to M.Sc. students
- Disseminating results through scientific publications and talks at conferences
Your Profile:
- M.Sc. degree in Computer Science, Applied Mathematics, Electrical Engineering, or a related field
- Strong mathematical and/or algorithmic CS background
- Good skills in programming
- Fluent written and verbal communication skills in English are mandatory
- Background in cryptography and information security (a plus)
The duration of a Ph.D is typically 3-4 years. The University offers highly competitive salaries and is an equal opportunity employer. You will work in an exciting international environment.
Applications, written in English, should include:
- Curriculum Vitae (including your contact address and email address, education, work experience, publications if any)
- Transcript of all modules and results from university-level courses taken
- A research statement indicating your interest, prior research (if any) and your motivation (max 1 page)
- Contact information for 2-3 referees
Closing date for applications: 15 January 2018
Contact: Dr. Alfredo Rial (e-mail: alfredo.rial (at) uni.lu)
More information: https://wwwen.uni.lu/snt/research/apsia
University of South Florida
Minimum Qualifications:
• A PhD in Computer Science, Electrical Engineering, Statistics, or related field completed within the past three years or soon to be completed.
• Research-level expertise in one (or more) of the following areas: – Privacy-enhancing technologies, – Machine Learning – Security and Applied Cryptography – IoT Security and Privacy – Big Data Analytics – Edge Computing
Preferred Qualifications:
• Candidates should have publications in high impact journals and conferences.
• The candidate should have strong programming skills including experience with Java, MATLAB, Pyton, and/or R.
Additional Information for Applicants:
A curriculum vitae, publication list, a cover letter/research statement outlining your research experience and interests, your research plans (not exceeding 2 pages), and the names of three academic/professional references.
Send the required documents to the email: brandeis.iastate_at_gmail_dot_com. To facilitate conveying the best image of your research, we recommend you attach to your application the two publications that you are most proud of.
Review of applications starts immediately and will continue until positions are filled.
Closing date for applications: 31 March 2018
Ryann Cartor, Daniel Smith-Tone
Hayo Baan, Sauvik Bhattacharaya, Oscar Garcia-Morchon, Ronald Rietman, Ludo Tolhuizen, Jose-Luis Torre-Arce, Zhenfei Zhang
In this work, we present Round2 that consists of a key-encapsulation mechanism and a public-key encryption scheme. Round2 is based on the General Learning with Rounding problem, that unifies the Learning with Rounding and Ring Learning with Rounding problems. Round2's construction using the above problem allows for a unified description and implementation. The key-encapsulation mechanism and public-key encryption scheme furthermore share common building blocks, simplifying (security and operational) analysis and code review. Round2's reliance on prime cyclotomic rings offers a large design space that allows fine-tuning of parameters to required security levels. The use of rounding reduces bandwidth requirements and the use of sparse-trinary secrets improves CPU performance and decryption success rates. Finally, Round2 includes various approaches of refreshing the system public parameter A, allowing efficient ways of preventing precomputation and back-door attacks.
Merav Parter, Eylon Yogev
While being quite an unfamiliar notion in the classical distributed setting, the notion of secure multi-party computation (MPC) is one of the main themes in the Cryptography community. Yet despite all extensive work in the area, no existing algorithm fits the framework of classical distributed models in which there are no assumptions on the graph topologies and only messages of bounded size are sent on the edges in each round.
In this paper, we introduce a new framework for \emph{secure distributed graph algorithms} and provide the first \emph{general compiler} that takes any "natural" non-secure distributed algorithm that runs in $r$ rounds, and turns it into a secure algorithm that runs in $\widetilde{O}(r \cdot D \cdot poly(\Delta))$ rounds where $\Delta$ is the maximum degree in the graph and $D$ is its diameter. We also show that this is nearly (existentially) optimal for any round-by-round compiler for bounded degree graphs.
The main technical part of our compiler is based on a new cycle cover theorem: We show that the edges of every bridgeless graph $G$ of diameter $D$ can be covered by a collection of cycles such that each cycle is of length $\widetilde{O}(D)$ and each edge of the graph $G$ appears in $\widetilde{O}(1)$ many cycles. In fact, our construction can be made instance optimal with respect to each single edge. Letting $C_e$ be the shortest cycle containing $e$ in $G$, our cycle collection contains a cycle of length $\widetilde{O}(|C_e|)$ that covers $e$ for every $e \in G$, and in addition, each edge appears on $\widetilde{O}(1)$ many cycles. As a result, our compiler becomes instance optimal for bounded degree graphs.
Ruben Niederhagen, Kai-Chun Ning, Bo-Yin Yang
Wen Wang, Jakub Szefer, Ruben Niederhagen
Claude Carlet, Stjepan Picek
Xinwei Gao, Jintai Ding, Saraswathy RV, Lin Li, Jiqiang Liu
Sailesh Simhadri, James Steel, Benjamin Fuller
To limit privacy violations, one can use fuzzy extractors to derive a stable cryptographic key from biometrics (Dodis et al., Eurocrypt 2004). Unfortunately, fuzzy extractors have not seen wide deployment due to insufficient security guarantees. Current fuzzy extractors provide no security for real biometric sources and no security if a user enrolls the same biometric with multiple devices or providers.
Previous work claims key derivation systems from the iris but only under weak adversary models. In particular, no known construction securely handles the case of multiple enrollments. Canetti et al. (Eurocrypt 2016) proposed a new fuzzy extractor called sample-then-lock.
We construct biometric key derivation for the iris starting from sample-then-lock. Achieving satisfactory parameters requires modifying and coupling of the image processing and the cryptography. Our construction is implemented in Python and being open-sourced. Our system has the following novel features:
-- 45 bits of security. This bound is pessimistic, assuming the adversary can sample strings distributed according to the iris in constant time. Such an algorithm is not known.
-- Secure enrollment with multiple services.
-- Natural incorporation of a password, enabling multifactor authentication. The structure of the construction allows the overall security to be sum of the security of each factor (increasing security to 79 bits).
Amin Rezaei, Yuanqi Shen, Shuyu Kong, Jie Gu, Hai Zhou
Vladimir Kolesnikov, Ahmad-Reza Sadeghi, Thomas Schneider
We describe efficient GC constructions for addition, subtraction, multiplication, and comparison functions. Our circuits for subtraction and comparison are approximately two times smaller (in terms of garbled tables) than previous constructions. This implies corresponding computation and communication improvements in SFE of functions using our efficient building blocks. The techniques rely on recently proposed ``free XOR'' GC technique.
Further, we present concrete and detailed improved GC protocols for the problem of secure integer comparison, and related problems of auctions, minimum selection, and minimal distance. Performance improvement comes both from building on our efficient basic blocks and several problem-specific GC optimizations. We provide precise cost evaluation of our constructions, which serves as a baseline for future protocols.
06 December 2017
1 December - 1 September 2018
Submission deadline: 1 February 2018
Notification: 1 April 2018
London (Guildford), United Kingdom, 9 September - 12 September 2018
Submission deadline: 16 April 2018
Notification: 18 June 2018