IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
24 April 2023
Wouter Castryck, Marc Houben, Simon-Philipp Merz, Marzio Mula, Sam van Buuren, Frederik Vercauteren
As an application, we identify weak instances of class group actions on elliptic curves assuming the degree of the secret isogeny is known. More in detail, we show that if $m^2 \mid \Delta_\mathcal{O}$ for some prime power $m$ then given two primitively $\mathcal{O}$-oriented elliptic curves $(E, \iota)$ and $(E',\iota') = [\mathfrak{a}] E,\iota)$ connected by an unknown invertible ideal $\mathfrak{a} \subseteq \mathcal{O}$, we can recover $\mathfrak{a}$ essentially at the cost of a discrete logarithm computation in a group of order $m^2$, assuming the norm of $\mathfrak{a}$ is given and is smaller than $m^2$. We give concrete instances, involving ordinary elliptic curves over finite fields, where this turns into a polynomial time attack.
Finally, we show that these self-pairings simplify known results on the decisional Diffie-Hellman problem for class group actions on oriented elliptic curves.
20 April 2023
Utrecht University, Department of Information and Computing Sciences; Utrecht, Netherlands
In this project, you will develop foundations and practical techniques to build software systems with reliable security guarantees. Depending on your background and interests, this project can focus on different security problems, including, for example, memory safety, software sandboxing, information-flow control systems, and defenses against side-channel and Spectre attacks.
Interested? Click on the title to know more and apply!
Deadline: 16 May 2023
Duration: 5 Years
Apply here: https://www.uu.nl/en/organisation/working-at-utrecht-university/jobs/phd-position-in-language-based-security-10-fte
Closing date for applications:
Contact: Marco Vassena, https://webspace.science.uu.nl/mvassena
More information: https://www.uu.nl/en/organisation/working-at-utrecht-university/jobs/phd-position-in-language-based-security-10-fte
University of Luxembourg
The CryptoLux group of the University of Luxembourg has a vacancy for a post-doctoral researcher in the area of security/privacy of blockchains and smart contracts. The successful candidate will contribute to a research project entitled Advanced Cryptography for Finance and Privacy (CryptoFin), which is funded by the Fonds National de la Recherche (FNR). Starting in September 2023, CryptoFin will run over a period of 3 years and be carried out in collaboration with the cryptography teams of Stanford University and Ethereum foundation. The mission of the CryptoFin project is to develop innovative solutions for some of the most pressing research problems in the blockchain domain, especially in the context of layer-2 protocols for off-chain transactions and the design of advanced cryptographic techniques like verifiable delay functions, proof-of-X systems with special features, and new MPC/SNARK-friendly primitives.
Candidates must hold a Ph.D. degree in cryptography, IT security, or a related field. Preference will be given to candidates with a strong publication record that includes at least one paper at an IACR conference/workshop or one of the top-4 security conferences. Experience in blockchains and/or smart contracts is a plus. Candidates with an interest to conduct research in one of the following areas are particularly encouraged to apply:
- Applied cryptography (especially design/analysis of symmetric cryptosystems)
- Cryptofinance and cryptoeconomics
- Privacy and anonymity on the Internet
The position is initially offered for 1 year, but an extension by 2 years is possible. The University of Luxembourg offers excellent working conditions and a highly competitive salary. Interested candidates are invited to send their application by email to Prof. Alex Biryukov before May 7, 2023 (early submission is encouraged). The application material should contain a cover letter explaining the candidate's research interests, a CV (incl. photo), a list of publications, scans of diploma certificates, and contact details of 3 references.
Closing date for applications:
Contact: Prof. Alex Biryukov (alex.biryukov@uni.lu)
More information: https://cryptolux.org/index.php/Vacancies
University of Luxembourg
The CryptoLux group of the University of Luxembourg has two vacancies for Ph.D. positions in the area of security/privacy of blockchains and smart contracts. The successful candidates will contribute to a research project entitled Advanced Cryptography for Finance and Privacy (CryptoFin), which is funded by the Fonds National de la Recherche (FNR). Starting in September 2023, CryptoFin will run over a period of 3 years and be carried out in collaboration with the cryptography teams of Stanford University and Ethereum foundation. The mission of the CryptoFin project is to develop innovative solutions for some of the most pressing research problems in the blockchain domain, especially in the context of layer-2 protocols for off-chain transactions and the design of advanced cryptographic techniques like verifiable delay functions, proof-of-X systems with special features, and new MPC/SNARK-friendly primitives.
Candidates must hold an M.Sc. degree (or earn an M.Sc. degree before September 2023) in computer science, mathematics, or a related field. Experience in blockchains and/or smart contracts is a plus. Candidates with an interest to conduct research in one of the following areas are particularly encouraged to apply:
- Applied cryptography (especially design/analysis of symmetric cryptosystems)
- Cryptofinance and cryptoeconomics
- Privacy and anonymity on the Internet
Both positions are fully funded and initially offered for 3 years, but an extension to a 4th year is possible. The University of Luxembourg offers excellent working conditions and a highly competitive salary. Interested candidates are invited to send their application by email to Prof. Alex Biryukov before May 7, 2023 (early submission is encouraged). The application material should contain a cover letter explaining the candidate's research interests, a CV (incl. photo), scans of diploma certificates, and contact details of 3 references.
Closing date for applications:
Contact: Prof. Alex Biryukov (alex.biryukov@uni.lu)
More information: https://cryptolux.org/index.php/Vacancies
19 April 2023
- Jung Hee Cheon, for influential contributions to algebraic cryptanalysis and fully homomorphic encryption, as well as outstanding service to IACR and the Asia-Pacific cryptography community.
- Stanisław Jarecki, for significant contributions to the development and standardization of distributed cryptography, as well as for service to IACR.
- Marc Joye, for practical and theoretical contributions to applied and industrial cryptography, and for contributions to IACR.
- Jesper Buus Nielsen, for fundamental contributions to cryptography and for service to IACR.
- Rafael Pass, for fundamental contributions to theoretical cryptography and service to the cryptography community.
- Giuseppe Persiano, for fundamental contributions to non-interactive zero knowledge and searchable encryption, as well as for service to the cryptography community.
- Reihaneh Safavi-Naini, for significant contributions to cryptography and its application to information security, and exemplary service to IACR and the cryptography community.
18 April 2023
Ahmet Ramazan Ağırtaş, Oğuz Yayla
Junrui Liu, Ian Kretz, Hanzhi Liu, Bryan Tan, Jonathan Wang, Yi Sun, Luke Pearson, Anders Miltner, Işıl Dillig, Yu Feng
17 April 2023
Technische Universität Darmstadt
Doctoral Researcher (Research Assistant/PhD Student) in Cryptography and Complexity Theory
in the group of Professor Marc Fischlin. More information about our research is available under www.cryptoplexity.de. The starting date is as soon as possible. The initial funding for the position is for three years, but the contract should be renewable. Candidates are expected to perform scientific research in the areas of the projects, and to contribute to the teaching, research, and administrative tasks of the group.
Your Profile:
• Master’s degree (or equivalent) in Computer Science, Mathematics, or a similar discipline,
• Extensive knowledge in the areas of cryptography and IT security,
• fluent English language skills,
• experience in IT system administration is welcome.
How to Apply
• curriculum vitae, including references,
• copies of relevant diplomas and certificates,
• research statement.
TU Darmstadt is an autonomous university with broad research excellence, interdisciplinary profile and clear emphases in engineering and information and communication technology. The Department of Computer Science is one of the leading CS departments in Europe and placed regularly in the top group in nationwide rankings. In the area of Cybersecurity, TU Darmstadt is one of the leading research institutions within Europe focusing on a broad spectrum of applied and theoretical research. The services rendered as part of the positions function as the scientific qualification of the candidate. The candidates will be given the opportunity to accomplish a doctoral degree.
The application data should be bundled into a single PDF file.
Closing date for applications:
Contact: Prof. Dr. Marc Fischlin, jobs@cx.tu-darmstadt.de
More information: https://www.cryptoplexity.informatik.tu-darmstadt.de/cryptoplexity/jobs_3/index.en.jsp
Agentur für Innovation in der Cybersicherheit "Innovation for Cybersecurity"
Closing date for applications:
Contact: Matthias Strauß, Head of HR, bewerbung@cyberagentur.de
More information: https://app.connectoor.de/jobview?jobid=62d506deddb233fc338b4579
Monash University, Melbourne, Australia
- Post-quantum cryptography (based on lattices and/or hash) and its applications e.g. to blockchain
- Zero-knowledge proofs and their applications e.g. to blockchain
- Blockchain protocols more broadly
- highly competitive tuition fee and stipend scholarships
- opportunities to collaborate with leading academic and industry experts in the related areas
- opportunities to participate in international grant-funded projects
- collaborative and friendly research environment
- an opportunity to live/study in one of the most liveable and safest cities in the world
Requirements. A strong mathematical background is required, but a strong cryptography background is not necessarily a must (but it’s of course a plus). Some knowledge/experience in coding (for example, Python, C/C++, SageMath) is also a plus. Candidates must have completed (or be about to complete within the next 6 months) a significant research component either as part of their undergraduate (honours) degree or masters degree. They should have excellent English verbal and written communication skills.
How to apply. please first refer to https://mfesgin.github.io/supervision/ for more information. Then, please email your CV and bachelor/master transcripts with the subject line "Prospective PhD Student - Your Name"
Closing date for applications:
Contact: Muhammed Esgin (firstname.lastname@monash.edu)
More information: https://mfesgin.github.io/supervision/
Arquimea Research Center ( ARQUIMEA)
Closing date for applications:
Contact: ARQUIMEA web page
More information: https://arquimea.bamboohr.com/careers/240
Brice Colombier, Vincent Grosso, Pierre-Louis Cayrel, Vlad-Florin Drăgoi
Jung Hee Cheon, Wonhee Cho, Jiseung Kim
The compiler is constructed in a modular fashion and includes a compact threshold fully homomorphic encryption, a non-interactive zero-knowledge proof with preprocessing, and a non-interactive commitment. An instantiation of the Universal Thresholdizer can be achieved through the construction of a compact threshold fully homomorphic encryption. Currently, there are two threshold fully homomorphic encryptions based on linear secret sharing, with one using Shamir's secret sharing and the other using the $\{0,1\}$-linear secret sharing scheme ($\{0,1\}$-LSSS). The former fails to achieve compactness as the size of its ciphertext is $O(N\log N)$, where $N$ is the number of participants in the distributed system. Meanwhile, the latter provides compactness, with a ciphertext size of $O(\log N)$, but requires $O(N^{4.3})$ share keys on each party, leading to high communication costs.
In this paper, we propose a communication-efficient Universal Thresholdizer by revisiting the threshold fully homomorphic encryption. Our scheme reduces the number of share keys required on each party to $O(N^{2+o(1)})$ while preserving the ciphertext size of $O(\log N)$. To achieve this, we introduce a new linear secret sharing scheme called TreeSSS, which requires a smaller number of shared keys and satisfies compactness. As a result, the Threshold Fully Homomorphic Encryption underlying our linear secret sharing scheme has fewer shared keys during the setup algorithm and reduced communication costs during the partial decryption algorithm. Moreover, the construction of a Universal Thresholdizer can be achieved through the use of TreeSSS, as it reduces the number of shared keys compared to previous constructions. Additionally, TreeSSS may be of independent interest, as it improves the efficiency in terms of communication costs when used to replace $\{0,1\}$-LSSS.
Jakub Klemsa, Melek Önen
Amit Behera, Zvika Brakerski, Or Sattath, Omri Shmueli
We show that, similarly to PRS, PRSPD can be constructed from any post-quantum one-way function. As far as the authors are aware, this is the first construction of a family of states that satisfies both pseudorandomness and provability of destruction. We show that many cryptographic applications that were shown based on PRS variants using quantum communication can be based on (variants of) PRSPD using only classical communication. This includes symmetric encryption, message authentication, one-time signatures, commitments, and classically verifiable private quantum coins.
Roberto La Scala, Federico Pintore, Sharwan K. Tiwari, Andrea Visconti
Having in mind cryptanalytic applications, we present an implementation of this strategy in an algorithm called MultiSolve which is designed for polynomial systems having at most one solution. We prove explicit formulas for its complexity which are based on probability distributions that can be easily estimated by performing the proposed preprocessing on a testset of evaluations for different subsets of variables. We prove that an optimal complexity of MultiSolve is achieved by using a full multistep strategy with a maximum number of steps and in turn the classical guess-and-determine strategy, which essentially is a strategy consisting of a single step, is the worst choice. Finally, we extensively study the behaviour of MultiSolve when performing an algebraic attack on the well-known stream cipher Trivium.
Han-Ting Chen, Yi-Hua Chung, Vincent Hwang, Chi-Ting Liu, Bo-Yin Yang
Arianna Gringiani, Alessio Meneghetti, Edoardo Signorini, Ruggero Susella
Alexander May, Carl Richard Theodor Schneider
In this work, we explicitly construct smooth auxiliary curves for a dozen of mostly used, standardized elliptic curves of bit-sizes in the range $[204,256]$, including e.g., NIST P-256, Curve25519, SM2 and GOST R34.10. For all these curves we construct a corresponding cyclic auxiliary curve $\hat E(\mathbb{F}_q)$, whose order is $39$-bit smooth, i.e., its largest factor is of bit-length at most $39$ bits.
This in turn allows us to compute for all divisors of the order of $\hat E(\mathbb{F}_q)$ exhaustively a codebook for all discrete logarithms. As a consequence, dlogs on $\hat E(\mathbb{F}_q)$ can efficiently be computed in a matter of seconds. Our resulting codebook sizes are less than 29 TByte, and fit on our hard disk.
We also construct auxiliary curves for NIST P-384 and NIST P-521 with a $65$-bit and $110$-bit smooth order.
Further, we provide an efficient implementation of Maurer's reduction from the dlog computation in $G$ with order $q$ to the dlog computation on its auxiliary curve $\hat E(\mathbb{F}_q)$. Let us provide a flavor of our results, e.g., when $G$ is the NIST P-256 group, the results for other curves are similar. With the help of our codebook for the auxiliary curve $\hat E(\mathbb{F}_q)$, and less than 24,000 calls to a DH oracle in $G$ (that we simulate), we can solve discrete logarithms on NIST P-256 in around 30 secs.
From a security perspective, our results show that for current elliptic curve standards the difficulty of solving DH is practically tightly related to the difficulty of computing dlogs. Namely, unless dlogs are easy to compute on these curves $G$, we provide a very concrete security guarantee that DH in $G$ must also be hard.
From a cryptanalytic perspective, our results show a way to efficiently solve discrete logarithms in the presence of a DH oracle. Thus, if practical implementations unintentionally provide a DH oracle, dlog computations actually become surprisingly easy.