International Association for Cryptologic Research

International Association
for Cryptologic Research

IACR News

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21 June 2018

Microsoft Research, Redmond WA, USA
Job Posting Job Posting
Description available at https://careers.microsoft.com/us/en/job/391591/SENIOR-RSDE

Closing date for applications: 1 August 2018

Contact: Kristin Lauter

Email: klauter (at) microsoft.com

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University of Lübeck, Germany
Job Posting Job Posting
The Institute for IT Security at the University of Lübeck invites applications for an open position as

Professor for Secure Software Systems (W2)

As future holder of the position, you should bring a proven scientific track record in IT Security, especially in at least one of the following areas:

  • Security of Complex and Networked Software Systems
  • Anonymity and Privacy
  • Operating Systems Security
  • Computer Forensics

You bring along a high potential for strengthening the profile of the new Institute for IT Security through research work, project management, and the acquisition of third party funds in the field of IT Security.

Your teaching tasks include participation in the courses of the degree programs of the Department of Computer Science/Engineering, especially in the new Bachelor’s and Master’s program in IT Security.

University of Lübeck offers excellent opportunities for interdisciplinary cooperation in the key areas of Computer Science, Medical Engineering, Robotics, e-Government, Data Science, as well as the Life Sciences and Medicine. In addition, the university supports activities in technology transfer.

For a detailed description of the position as well as necessary templates and further information on the application process, please visit the link below.

Closing date for applications: 18 July 2018

Contact: Susanne Markmann,

Büro der MINT-Sektionen

Email: mint.buero (at) uni-luebeck.de

More information: https://www.uni-luebeck.de/structure/sektionen/sektionen-mint/berufungsverfahren-stellen.html

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Technische Universität Darmstadt in Darmstadt, Germany
Job Posting Job Posting
Applications are invited for two full-time Pre-doc positions in the Security in Information Technology (SIT) Research Group at Technische Universität Darmstadt, Germany, under the direction of Prof. Dr. Michael Waidner.

We are looking for candidates interested in working at the intersection of privacy engineering, and applied cryptography. This project addresses two central challenges in the provision of cloud services: (1) client privacy, and (2) verifiable metering and billing. For challenge (1), we design and develop anonymous communication mechanisms for the cloud. For challenge (2), we build techniques for service verification and design an infrastructure for verifiable metering and billing, enabling clients to verify in real-time their service consumption and corresponding charges. By solving and combining both challenges we obtain privacy-preserving verifiable metering and billing. Further details on the project can be found here.

The vacancy is within the Collaborative Research Center CROSSING, funded by DFG, the German Research Foundation. Collaborative Research Centers are institutions funded by the German Research Foundation (DFG) and are established at universities to pursue a scientifically ambitious, complex, longterm research program. The goal of the center CROSSING is to provide cryptography-based security solutions enabling trust in new and next generation computing environments. For more information about CROSSING please visit www.crossing.tu-darmstadt.de.

As part of its research program CROSSING will develop an opensource software called OpenCCE which will allow users to deploy the developed solutions in a secure and easy way.

Applications will be considered until the positions are filled.

Closing date for applications: 30 September 2018

Contact: Applicants are kindly requested to send their applications to staff-sit (at) crisp-da.de with the subject “Funded PhD position in CRC CROSSING” and a single pdf (< 10MB).

More information: https://www.sit.informatik.tu-darmstadt.de

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20 June 2018

Toronto, Canada, 15 October 2018
Event Calendar Event Calendar
Event date: 15 October 2018
Submission deadline: 25 July 2018
Notification: 15 August 2018
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18 June 2018

Universite Libre de Bruxelles, Belgium
Job Posting Job Posting
Applications are invited for a one-year Post-Doc position in the Quality and Computer Security Research Lab and the Algorithmic Group of the Université Libre de Bruxelles.

The successful applicant will work on the analysis and design of searchable encryption schemes and on data structures enabling efficient search operations on encrypted data.

Candidates shall hold a PhD degree in Computer Science or related field, should have experience in the research field of the position and should be fluent in English.

Applications must include:

- A Curriculum Vitae

- A motivation letter

- The list of publications and a copy of three selected publications

- The copies of diplomas and certificates

- Two (or more) reference letters

- The date from which the applicant will be available

Applications must be sent to olivier.markowitch (at) ulb.ac.be and stefan.langerman (at) ulb.ac.be

Closing date for applications: 1 October 2018

Contact: Olivier Markowitch, Universite Libre de Bruxelles, Computer Science Department, olivier.markowitch (at) ulb.ac.be

More information: https://qualsec.ulb.ac.be/about-2/post-doc-position/

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University of Luxembourg
Job Posting Job Posting
The successful candidate will join the APSIA group led by Prof. Peter Y. A. Ryan. The candidate will be part of the Eureopean H2020 project “FutureTPM”, and will conduct research on the design and analysis of quantum-safe Trusted Platform Modules (TPM). The candidate will be supervised by Prof. Peter Y. A. Ryan and Dr. Alfredo Rial. The candidate’s tasks include the following:

Shaping research directions and producing results in one or more of the following topics:

Develop and analyse quantum-safe algorithms and protocols.

Explore the incorporation of quantum-safe algorithms in a TPM architecture.

Define security properties and models for a TPM against quantum adversaries.

Coordinating research projects and delivering outputs

Collaborating with partners in the FutureTPM project

Providing guidance to PhD and MSc students

Disseminating results through scientific publications

Closing date for applications: 6 July 2018

Contact: Peer Y A Ryan, peter.ryan (at) uni.lu or Alfredo Rial, alfredo.rial (at) uni.lu

More information: http://emea3.mrted.ly/1vbm4

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University of Luxembourg
Job Posting Job Posting
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) funded project “Quantum Communication with Deniability”, which starts 1st July 2018 and will conduct research on enabling “deniability” using both classical and quantum mechanisms. The candidate will be supervised by Prof. Peter Y. A. Ryan and Dr. Peter Roenne. The candidate’s tasks include the following:

Research on the following topics in quantum cryptography and information theory:

Exploring formal definitions of the notion of deniability against various threat models.

Exploring the limits of what is achievable in terms of deniability using both classical and quantum mechanisms.

Designing and analysing novel protocols and mechanisms to achieve stronger forms of deniability.

Providing guidance to M.Sc. students

Closing date for applications: 6 July 2018

Contact: P Y A Ryan, peter.ryan (at) uni.lu

More information: http://emea3.mrted.ly/1vblq

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Melissa Chase, Apoorvaa Deshpande, Esha Ghosh
ePrint Report ePrint Report
In recent years, some of the most popular online chat services such as iMessage and WhatsApp have deployed end-to-end encryption to mitigate some of the privacy risks to the transmitted messages. But facilitating end-to-end encryption requires a Public Key Infrastructure (PKI), so these services still require the service provider to maintain a centralized directory of public keys. A downside of this design is placing a lot of trust in the service provider; a malicious or compromised service provider can still intercept and read users' communication just by replacing the user's public key with one for which they know the corresponding secret. A recent work by Melara et al. builds a system called CONIKS where the service provider is required to prove that it is returning a consistent for each user. This allows each user to monitor his own key and reduces some of the risks of placing a lot of trust in the service provider. New systems [EthIKS,Catena] are already being built on CONIKS. While these systems are extremely relevant in practice, the security and privacy guarantees of these systems are still based on some ad-hoc analysis rather than on a rigorous foundation. In addition, without modular treatment, improving on the efficiency of these systems is challenging. In this work, we formalize the security and privacy requirements of a verifiable key service for end-to-end communication in terms of the primitive called {\em Verifiable Key Directories} (VKD). Our abstraction captures the functionality of all three existing systems: CONIKS, EthIKS and Catena. We quantify the leakage from these systems giving us a better understanding of their privacy in concrete terms. Finally, we give a VKD construction (with concrete efficiency analysis) which improves significantly on the existing ones in terms of privacy and efficiency. Our design modularly builds from another primitive that we define as append-only zero knowledge sets (aZKS) and from append-only Strong Accumulators. By providing modular constructions, we allow for the independent study of each of these building blocks: an improvement in any of them would directly result in an improved VKD construction. Our definition of aZKS generalizes the definition of the zero knowledge set for updates, which is a secondary contribution of this work, and can be of independent interest.
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Antonio Faonio, Jesper Buus Nielsen, Mark Simkin, Daniele Venturi
ePrint Report ePrint Report
Non-malleable codes for the split-state model allow to encode a message into two parts, such that arbitrary independent tampering on each part, and subsequent decoding of the corresponding modified codeword, yields either the same as the original message, or a completely unrelated value. Continuously non-malleable codes further allow to tolerate an unbounded (polynomial) number of tampering attempts, until a decoding error happens. The drawback is that, after an error happens, the system must self-destruct and stop working, otherwise generic attacks become possible.

In this paper we propose a solution to this limitation, by leveraging a split-state refreshing procedure. Namely, whenever a decoding error happens, the two parts of an encoding can be locally refreshed (i.e.,\ without any interaction), which allows to avoid the self-destruct mechanism in some applications. Additionally, the refreshing procedure can be exploited in order to obtain security against continual leakage attacks. We give an abstract framework for building refreshable continuously non-malleable codes in the common reference string model, and provide a concrete instantiation based on the external Diffie-Hellman assumption.

Finally, we explore applications in which our notion turns out to be essential. The first application is a signature scheme tolerating an arbitrary polynomial number of split-state tampering attempts, without requiring a self-destruct capability, and in a model where refreshing of the memory happens only after an invalid output is produced. This circumvents an impossibility result from a recent work by Fuijisaki and Xagawa (Asiacrypt 2016). The second application is a compiler for tamper-resilient read-only RAM programs. In comparison to other tamper-resilient RAM compilers, ours has several advantages, among which the fact that, in some cases, it does not rely on the self-destruct feature.
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Yin Li, Yu Zhang, Xiaoli Guo, Chuanda Qi
ePrint Report ePrint Report
In this paper, we propose a new type of non-recursive Mastrovito multiplier for $GF(2^m)$ using a $n$-term Karatsuba algorithm (KA), where $GF(2^m)$ is defined by an irreducible trinomial, $x^m+x^k+1, m=nk$. We show that such a type of trinomial combined with the $n$-term KA can fully exploit the spatial correlation of entries in related Mastrovito product matrices and lead to a low complexity architecture. The optimal parameter $n$ is further studied. As the main contribution of this study, the lower bound of the space complexity of our proposal is about $O(\frac{m^2}{2}+m^{3/2})$. Meanwhile, the time complexity matches the best Karatsuba multiplier known to date. To the best of our knowledge, it is the first time that Karatsuba-based multiplier has reached such a space complexity bound while maintaining relatively low time delay.
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Matvei Kotov, Anton Menshov, Alexander Ushakov
ePrint Report ePrint Report
We analyze security properties of a two-party key-agreement protocol recently proposed by I. Anshel, D. Atkins, D. Goldfeld, and P. Gunnels, called Kayawood protocol. At the core of the protocol is an action (called E-multiplication) of a braid group on some finite set. The protocol assigns a secret element of a braid group to each party (private key). To disguise those elements, the protocol uses a so-called cloaking method that multiplies private keys on the left and on the right by specially designed elements (stabilizers for E-multiplication).

We present a heuristic algorithm that allows a passive eavesdropper to recover Alice's private key by removing cloaking elements. Our attack has 100% success rate on randomly generated instances of the protocol for the originally proposed parameter values and for recent proposals that suggest to insert many cloaking elements at random positions of the private key. Our implementation of the attack is available on GitHub.
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Ignacio Cascudo, René Bødker Christensen, Jaron Skovsted Gundersen
ePrint Report ePrint Report
We consider recent constructions of $1$-out-of-$N$ OT-extension from Kolesnikov and Kumaresan (CRYPTO 2013) and from Orrú et al. (CT-RSA 2017), based on binary error-correcting codes. We generalize their constructions such that $q$-ary codes can be used for any prime power $q$. This allows to reduce the number of base $1$-out-of-$2$ OT's that are needed to instantiate the construction for any value of $N$, at the cost of increasing the complexity of the remaining part of the protocol. We analyze these trade-offs in some concrete cases.
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Kyle Hogan, Hoda Maleki, Reza Rahaeimehr, Ran Canetti, Marten van Dijk, Jason Hennessey, Mayank Varia, Haibin Zhang
ePrint Report ePrint Report
OpenStack is the prevalent open-source, non-proprietary package for managing cloud services and data centers. It is highly complex and consists of multiple inter-related components which are developed by separate, loosely coordinated groups. We initiate an effort to provide a rigorous and holistic security analysis of OpenStack. Our analysis has the following key features:

-It is user-centric: It stresses the security guarantees given to users of the system, in terms of privacy, correctness, and timeliness of the services.

-It provides defense in depth: It considers the security of OpenStack even when some of the components are compromised. This departs from the traditional design approach of OpenStack, which assumes that all services are fully trusted.

-It is modular: It formulates security properties for individual components and uses them to assert security properties of the overall system.

We base our modeling and security analysis in the universally composable (UC) security framework, which has been so far used mainly for analyzing security of cryptographic protocols. Indeed, demonstrating how the UC framework can be used to argue about security-sensitive systems which are mostly non-cryptographic in nature is another main contribution of this work.

Our analysis covers only a number of core components of OpenStack. Still, it uncovers some basic and important security trade-offs in the design. It also naturally paves the way to a more comprehensive analysis of OpenStack.
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Dan Boneh, Joseph Bonneau, Benedikt Bünz, Ben Fisch
ePrint Report ePrint Report
We study the problem of building a verifiable delay function (VDF). A VDF requires a specified number of sequential steps to evaluate, yet produces a unique output that can be efficiently and publicly verified. VDFs have many applications in decentralized systems, including public randomness beacons, leader election in consensus protocols, and proofs of replication. We formalize the requirements for VDFs and present new candidate constructions that are the first to achieve an exponential gap between evaluation and verification time.
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Gaurav Bansod, Abhijit Patil, Narayan Pisharoty
ePrint Report ePrint Report
In this paper we proposed an ultra-lightweight cipher GRANULE. It is based on Feistel network which encrypts 64 bits of data with 80/128 bits of key. GRANULE needs very less memory space as compared to existing lightweight ciphers .GRANULE needs 1288 GEs for 80 bit and 1577 GEs for 128 bit key size. It also shows good resistance against linear and differential cryptanalysis. GRANULE needs very small footprint area and provides robust secure design which thwart attacks like biclique attack, zero correlation attack, meet in the middle attack ,key schedule attack and key collision attack. GRANULE is having a strong S-box which is the key designing aspect in any cipher design. In this paper GRANULE is proposed with 32 rounds which are enough to provide resistance against all possible types of attacks. GRANULE consumes very less power as compared to other modern lightweight ciphers. We believe GRANULE cipher is the best suited cipher for providing robust security in applications like IoT.
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Lucas Schabh{\"u}ser, Denis Butin, Johannes Buchmann
ePrint Report ePrint Report
Sensitive data is often outsourced to cloud servers, with the server performing computation on the data. Computational correctness must be efficiently verifiable by a third party while the input data remains confidential. This paper introduces CHQS, a homomorphic signature scheme from bilinear groups fulfilling these requirements. CHQS is the first such scheme to be both context hiding and publicly verifiable for arithmetic circuits of degree two. It also achieves amortized efficiency: after a precomputation, verification can be faster than the evaluation of the circuit itself.
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Vlad Constantin Craciun, Andrei Mogage, Emil Simion
ePrint Report ePrint Report
The ransomware nightmare is taking over the internet impacting common users,small businesses and large ones. The interest and investment which are pushed into this market each month, tells us a few things about the evolution of both technical and social engineering and what to expect in the short-coming future from them. In this paper we analyze how ransomware programs developed in the last few years and how they were released in certain market segments throughout the deep web via RaaS, exploits or SPAM, while learning from their own mistakes to bring profit to the next level. We will also try to highlight some mistakes that were made, which allowed recovering the encrypted data, along with the ransomware authors preference for specific encryption types, how they got to distribute, the silent agreement between ransomwares, coin-miners and bot-nets and some edge cases of encryption, which may prove to be exploitable in the short-coming future.
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Lauren De Meyer, Begül Bilgin, Oscar Reparaz
ePrint Report ePrint Report
This paper revisits the security conditions of masked hardware implementations. We describe a new, succinct, information-theoretic condition to ensure security in the presence of glitches. This single condition includes, but is not limited to, previous security notions such as those used in threshold implementations. As a consequence, we can prove the security of masked functions that work with non-uniform input sharings. Our notion naturally generalizes to higher orders. Furthermore, we can apply our condition in a tool that efficiently tests and validates the resistance of masked hardware circuits against DPA. Finally, we also treat the notion of (strong) non-interference from an information-theoretic point-of-view in order to unify the different security concepts and pave the way to the verification of composability in the presence of glitches.
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Ivan Damgård, Tomasz Kazana, Maciej Obremski, Varun Raj, Luisa Siniscalchi
ePrint Report ePrint Report
Non-Malleable Codes (NMC) were introduced by Dziembowski, Pietrzak and Wichs in ICS 2010 as a relaxation of error correcting codes and error detecting codes. Faust, Mukherjee, Nielsen, and Venturi in TCC 2014 introduced an even stronger notion of non-malleable codes called continuous non-malleable codes where security is achieved against continuous tampering of a single codeword without re-encoding. We construct information theoretically secure CNMC resilient to bit permutations and overwrites, this is the first Continuous NMC constructed outside of the split-state model. In this work we also study relations between the CNMC and parallel CCA commitments. We show that the CNMC can be used to bootstrap a \sd\ parallel CCA bit commitment to a \sd\ parallel CCA string commitment, where \sd\ parallel CCA is a weak form of parallel CCA security. Then we can get rid of the \sd\ limitation obtaining a parallel CCA commitment, requiring only one-way functions.
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Subhrajyoti Deb, Bubu Bhuyan, Sartaj Ul Hasan
ePrint Report ePrint Report
Randomness testing of binary sequences generated by any keystream generator is of paramount importance to both designer and attacker. Here we consider a word-oriented keystream generator known as multiple-recursive matrix generator, which was introduced by Niederreiter (1993). Using NIST statistical test suite as well as DieHarder statistical package, we analyze randomness properties of binary sequences generated by multiple-recursive matrix generator and show that these sequences are not really adequate for any cryptographic applications. We also propose nonlinearly filtered multiple-recursive matrix generator based a special nonlinear function and establish that sequences generated by such a nonlinearly filtered multiple-recursive matrix generator provide good randomness results. Moreover, we compare our randomness test results with some of the recent lightweight stream ciphers like Lizard, Fruit, and Plantlet.
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