IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
23 October 2020
University of Surrey, Department of Computer Science, UK
Job PostingTopics of interest: distributed/concurrent systems, blockchain, internet data science or social computing, with links to security and/or AI.
Closing deadline: November 22, 2020
See https://jobs.surrey.ac.uk/vacancy.aspx?ref=045220
Closing date for applications:
Contact: Informal inquiries to Mark Manulis (m dot manulis at surrey dot ac dot uk)
More information: https://jobs.surrey.ac.uk/vacancy.aspx?ref=045220
Ruhr University Bochum, Germany
Job PostingThe group offers excellent working environment as a part of Horst Görtz Institut for IT Security (HGI https://hgi.rub.de/en/ ) including more than 200 scientists active in several different aspects of IT security and cryptography.
The candidate should have a PhD in IT-security, electrical engineering, computer engineering, or computer science with excellent publication records.
Since the position is funded by a national project, having the ability to fluently talk, write, and read in German is a must. The position is for two years, with an option to extend.
Send your application in a single pdf file to amir.moradi (at) rub.de
Closing date for applications:
Contact: Amir Moradi
More information: https://www.seceng.rub.de/moradi/
NYU Shanghai
Job PostingClosing date for applications:
Contact: shanghai.faculty.recruitment@nyu.edu
More information: https://apply.interfolio.com/80168
Center for Information Security and Trust, IT University of Copenhagen
Job PostingThe Center for Information Security and Trust (CISAT) at the Computer Science Department of the IT University of Copenhagen invites highly motivated individuals to apply for a Postdoc position starting in January 2021 or soon thereafter for a duration of 2 years.
The position is in the context of the project “Enabling User-Accountable Mechanisms for Decision Systems”, which looks at ways to provide dispute resolution capabilities to decision systems (e.g. voting protocols) by combining cryptographic techniques for human senses with advanced cryptographic protocols.
Closing date for applications:
Contact: Rosario Giustolisi (rosg@itu.dk) or Carsten Schürmann (carsten@itu.dk)
More information: https://candidate.hr-manager.net/ApplicationInit.aspx?cid=119&ProjectId=181223&DepartmentId=3439&MediaId=5
Lund University, Sweden
Job PostingClosing date for applications:
Contact: Thomas johansson (thomas@eit.lth.se)
More information: https://lu.varbi.com/en/what:job/jobID:358175/
Athena Research Center
Job PostingInterested candidates are advised to contact the coordinator (see details below) for further clarifications.
PhD candidates are expected to hold a Master’s degree (or equivalent) in Computer Science or related disciplines and with a strong interest in the field of security in the aforementioned fields. Excellent working knowledge of English is required.
Post-Doc candidates are expected to hold a PhD degree the fields of Computer Security of Machine Learning, have experience in EU funded projects and excellent working knowledge of English.
Deadline for applications 3/11/2020.Closing date for applications:
Contact: Prof. Constantinos Patsakis (kpatsak@unipi.gr)
More information: https://www.imsi.athenarc.gr/el/announcements/announcement/464
National Institute of Technology Jamshedpur, Jamshedpur, India
Job PostingClosing date for applications:
Contact: Sumit Kumar Debnath (PI)
More information: http://www.nitjsr.ac.in/uploads/index.php?id=3524&category=notifications
Kristian Gjøsteen, Thomas Haines, Morten Rotvold Solberg
ePrint ReportAnders Dalskov, Daniel Escudero, Marcel Keller
ePrint ReportWe implement our four-party protocol with abort in the MP-SPDZ framework for multiparty computation and benchmark multiple applications like MNIST classification training and ImageNet inference. Our results show that our four-party protocol performs similarly to an efficient honest-majority three-party protocol that only provides semi-honest/passive security, which suggest that adding a fourth party can be an effective method to achieve active security without harming performance.
Pratyay Mukherjee
ePrint ReportIn this work we augment the DiSE TSE definitions to the fully adaptive (and malicious) setting, in that the adversary is allowed to corrupt parties dynamically at any time during the execution. The adversary may choose to corrupt a party depending on the information acquired thus far, as long as the total number of corrupt parties stays below the threshold. We also augment DiSEs DPRF definitions to support adaptive corruption. We show that their generic TSE construction, when plugged-in with an adaptive DPRF (satisfying our definition), meets our adaptive TSE definitions.
We provide an efficient instantiation of the adaptive DPRF, proven secure assuming decisional Diffie-Hellman assumption (DDH), in the random oracle model. Our construction borrows ideas from Naor, Pinkas and Reingolds [Eurocrypt 1999] statically secure DDH-based DPRF (used in DiSE) and Libert, Joye and Yungs [PODC 2014] adaptively secure threshold signature. Similar to DiSE, we also give an extension satisfying a strengthened adaptive DPRF definition, which in turn yields a stronger adaptive TSE scheme. For that, we construct a simple and efficient adaptive NIZK protocol for proving a specific commit-and-prove style statement in the random oracle model assuming DDH.
Zichen Gui, Kenneth G. Paterson, Sikhar Patranabis, Bogdan Warinschi
ePrint ReportJoël Alwen, Daniel Jost, Marta Mularczyk
ePrint ReportThe cryptographic core of the MLS protocol (from which it inherits essentially all of its efficiency and security properties) is a Continuous Group Key Agreement (CGKA) protocol. CGKA protocols provide asynchronous E2E secure group management by allowing group members to agree on a fresh independent symmetric key after every change to the group's state (e.g. when someone joins/leaves the group).
In this work, we make progress towards a precise understanding of the insider security of MLS in the form of 3 contributions. On the theory side, we overcome several subtelties to formulate the first notion of insider security for a CGKA (or group messaging) protocol. Next, we isolate the core components of MLS to obtain a CGKA protocol we dubbed Insider Secure TreeKEM (ITK). Finally, we give a rigorous proof that ITK provides (adaptive) insider security. In particular, this work also initiates the study of insider secure CGKA protocols, a primitive of interest in its own right.
Chris Brzuska, Geoffroy Couteau
ePrint ReportOur results lay the foundations for a program towards building fine-grained one-way functions from strong forms of average-case hardness, following the template of constructions in the Random Language Model. We provide a preliminary investigation of this program, showing black-box barriers toward instantiating our idealized constructions from natural hardness properties.
Adrián Ranea, Bart Preneel
ePrint ReportIn this work, we analyse the security of white-box implementations based on self-equivalence encodings for a broad class of SPN ciphers. First, we characterize the self-equivalence groups of S-box layers, and we prove that all the self-equivalences of a cryptographically strong S-box layer have a diagonal shape. Then, we propose the first generic attack on self-equivalence encodings. Our attack, based on affine equivalence problems, identifies the connection between the security of self equivalence encodings and the self-equivalence structure of the cipher components. While we show that traditional SPN ciphers with cryptographically strong S-box layers cannot be secured with self-equivalence encodings, our analysis shows that self-equivalence encodings resist the generic attack if the cipher components satisfy several conditions, revealing the potential of self-equivalence encodings to secure other types of ciphers.
Aniruddha Biswas, Palash Sarkar
ePrint ReportWard Beullens, Lucas Disson, Robi Pedersen, Frederik Vercauteren
ePrint ReportSebastian Paul, Patrik Scheible
ePrint ReportAkinori Hosoyamada, Tetsu Iwata
ePrint ReportSubhadeep Banik, Zhenzhen Bao, Takanori Isobe, Hiroyasu Kubo, Fukang Liu, Kazuhiko Minematsu, Kosei Sakamoto, Nao Shibata, Maki Shigeri
ePrint ReportOhad Barta, Yuval Ishai, Rafail Ostrovsky, David J. Wu
ePrint ReportIn this work, we first construct a concretely-efficient designated-verifier (preprocessing) SNARG with inverse polynomial soundness, where the proof consists of just 2 group elements in a standard (generic) group. This leads to a 50% reduction in concrete proof size compared to Groth's construction. We follow the approach of Bitansky et al. (TCC 2013) who describe a compiler from linear PCPs to SNARGs in the preprocessing model. Our improvement is based on a new linear PCP packing technique that allows us to construct 1-query linear PCPs which can then be compiled into a SNARG (using ElGamal encryption over a generic group). An appealing feature of our new SNARG is that the verifier can precompute a statement-independent lookup table in an offline phase; verifying proofs then only requires 2 exponentiations and a single table lookup. This makes our new designated-verifier SNARG appealing in settings that demand fast verification and minimal communication.
We then turn to the question of constructing arguments where the proof consists of a single group element. Here, we first show that any (possibly interactive) argument for a language L where the verification algorithm is "generic" (i.e., only performs generic group operations) and the proof consists of a single group element, implies a witness encryption scheme for L. We then show that under a yet-unproven, but highly plausible, hypothesis on the hardness of approximating the minimal distance of linear codes, we can construct a 2-message laconic argument for NP where the proof consists of a single group element. Under the same hypothesis, we obtain a witness encryption scheme for NP in the generic group model. Along the way, we show that under a conceptually-similar but proven hardness of approximation result, there is a 2-message laconic argument for NP with negligible soundness error where the prover's message consists of just 2 group elements. In both settings, we obtain laconic arguments (and linear PCPs) with linear decision procedures. Our constructions circumvent a previous lower bound by Groth on such argument systems with linear decision procedures by relying on imperfect completeness. Namely, our constructions have vanishing but not negligible completeness error, while the lower bound of Groth implicitly assumes negligible completeness error of the underlying argument. Our techniques thus highlight new avenues for designing linear PCPs, succinct arguments, and witness encryption schemes.