IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
21 September 2023
Nina Bindel, Nicolas Gama, Sandra Guasch, Eyal Ronen
Kaiyi Zhang, Qingju Wang, Yu Yu, Chun Guo, Hongrui Cui
However, the exact hardness of these new one-way functions deserves further study and scrutiny. This work presents algebraic attacks on RAIN and AIM for certain instances, where one-round Rain can be compromised in $2^{n/2}$ for security parameter $n\in \{128,192,256\}$, and two-round Rain can be broken in $2^{120.3}$, $2^{180.4}$, and $2^{243.1}$ encryptions, respectively. Additionally, we demonstrate an attack on AIM-III (which aims at 192-bit security) with a complexity of $2^{186.5}$ encryptions. These attacks exploit the algebraic structure of the power function over fields with characteristic 2, which provides potential insights into the algebraic structures of some symmetric primitives and thus might be of independent interest.
David Jacquemin, Anisha Mukherjee, Ahmet Can Mert, Sujoy Sinha Roy
Ronan Lashermes, Hélène Le Bouder
Specifically, we demonstrate the feasibility of reconstructing a symmetric cryptographic cipher, even in scenarios where traces are sampled with information loss and noise, such as when measuring the power consumption of the chip.
EURECOM; Sophia Antipolis, France
Closing date for applications:
Contact: Antonio Faonio
More information: https://www.eurecom.fr/en/job/zero-knowledge-proofs
NUS-Singapore and the University of Sheffield, UK
Closing date for applications:
Contact: Dr Prosanta Gope (p.gope@sheffield.ac.uk)
University of Luxembourg, Esch-sur-Alzette, 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 October 15, 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)
AIT Austrian Institute of Technology; Vienna, Austria
Requirements:
- PhD degree in Computer Science, Cyber Security, or a related field, with a specialization on cryptology
- Profound knowledge in (public key) cryptography, including, e.g., federated computation, long-term and post-quantum secure communication, privacy-enhancing technologies, real-world crypto, zero-knowledge proofs and zkSNARKs
- Strong track record with publications at competitive academic conferences or journals (e.g., Crypto, Eurocrypt, Asiacrypt, TCC, PKC, CCS, S&P, USENIX, ESORICS, ...)
- Experience in the acquisition and execution of national and transnational research projects (e.g., H2020) is a plus
- Good knowledge of a programming language (e.g., C/C++, Rust, Java, Python) and software development is a plus
- Very good written and oral English skills; knowledge of German is not a requirement but willingness to learn German is expected
Please submit your application including CV, cover letter, full list of publications, and contact details of at least 2 references via email to: stephan.krenn[at]ait.ac.at
Closing date for applications:
Contact: Stephan Krenn; stephan.krenn[at]ait.ac.at
University of Birmingham, UK
This is an exciting opportunity to join the University of Birmingham’s Centre for Cyber Security and Privacy on the EPSRC funded project "IOTEE: Securing and analysing trusted execution beyond the CPU", led by Prof Oswald and Prof Ryan.
Trusted Execution Environments (TEEs) allow users to run their software in a secure enclave while assuring the integrity and confidentiality of data and applications. However, cloud computing these days relies heavily on peripherals (connected through PCIe) such as GPUs and FPGAs. In this project, together with researchers at the University of Southampton, we will thoroughly evaluate the security guarantees of the new TEE support in the PCIe standard. This could involve the use of formal modelling, as well as researching various software and hardware attacks and countermeasures against them.
We are looking for a person with a PhD in cyber security/computer science/electrical engineering. The candidate must have experience areas such as embedded security, binary analysis, physical attacks such as side-channel analysis and fault injection, and/or formal modelling. This needs to be evidenced through publications in highly ranked conferences/journals in the field. We also welcome experience in writing system level or low-level code in programming languages such as C, C++, or Rust.
The successful candidate will be employed on a full-time, fixed-term contract up to August 2026. Full-time starting salary is normally in the range £33,348 to £43,155. (Some) remote work is possible, depending on the circumstances. The University provides a range of employee benefits, as well as opportunities for career development and training. The project includes substantial funding for conference travel and equipment.
The post-doc will be working in the Centre for Cyber Security and Privacy, which currently has 14 permanent academics as well as 21 postdocs/PhD students.
The application deadline is 12 Oct 2023. Applications have to be made online at: https://edzz.fa.em3.oraclecloud.com/hcmUI/CandidateExperience/en/sites/CX_6001/job/2681/
Closing date for applications:
Contact: Informal enquiries can be made to David Oswald d.f.oswald@bham.ac.uk.
More information: https://edzz.fa.em3.oraclecloud.com/hcmUI/CandidateExperience/en/sites/CX_6001/job/2681/
Paderborn University, Department of Computer Science, Paderborn, Germany
Postdoc (f/m/d) (salary is according to E13 TV-L)
A position with 100 % of the regular working hours is available as of the next possible date. The employment is initially limited to three years and is based on the legal regulations of the Wissen-schaftszeitvertragsgesetzes (WissZeitVG).
Your duties and responsibilities:
• Establishment and expansion of an infrastructure for the integration of quantum computing in high-performance computing.
• Interface of PhoQS to the Paderborn Center for Parallel Computing (PC2) of the Paderborn University
• Supporting users, especially in the natural sciences, in the development and implementation of quantum algorithms
• Optimisation of quantum software platforms for photonic and gate-based quantum computing such as Strawberry Fields, Parceval or Qiskit in collaboration with HPC experts of the PC2
• Organisation and delivery of tutorials and workshops on the use of quantum software plat-forms (basic to advanced)
• Leading a team for the technical integration of quantum computing and high-performance computing
Hiring requirements:
• Completed PhD in computer science, mathematics or physics or comparable qualification
• Solid understanding of many-body quantum mechanics
• Practical experience in high-performance computing and/or in the use of quantum software platforms
• High motivation and willingness for interdisciplinary cooperation between computer science and physics
• Good knowledge of German and English, both written and spoken
• Friendliness, flexibility, ability to work in a team, initiative and willingness to work independently
Closing date for applications:
Contact: Please send your application including a CV (preferably in a single pdf file) using the Ref. No. 6105 by 30th September, 2023 to: bloemer@upb.de
More information: https://cs.uni-paderborn.de/en/cuk
18 September 2023
Omer Paneth, Rafael Pass
As an application of mergeable delegation, we obtain a construction of incrementally verifiable computation (IVC) (with polylogarithmic length proofs) for any (unbounded) polynomial number of steps based on LWE; as far as we know, this is the first such construction based on any falsifiable (as opposed to knowledge-extraction) assumption. The central building block that we rely on, and construct based on LWE, is a rate-1 batch argument (BARG): this is a non-interactive argument for NP that enables proving $k$ NP statements $x_1,..., x_k$ with communication/verifier complexity $m+o(m)$, where $m$ is the length of one witness. Rate-1 BARGs are particularly useful as they can be recursively composed a super-constant number of times.
Prashant Agrawal, Kabir Tomer, Abhinav Nakarmi, Mahabir Prasad Jhanwar, Subodh Sharma, Subhashis Banerjee
Yi Liu, Junzuo Lai, Qi Wang, Xianrui Qin, Anjia Yang, Jian Weng
However, in the cases where misbehavior goes undetected (\eg with a probability of $10\%$), \emph{no security guarantee is provided for the honest party}, potentially resulting in a complete loss of input privacy and output correctness.
In this paper, we tackle this critical problem by presenting a highly effective solution. We introduce and formally define an enhanced notion called \emph{robust PVC security}, such that even if the misbehavior remains undetected, the malicious party can only gain an additional $1$-bit of information about the honest party's input while maintaining the correctness of the output. We propose a novel approach leveraging \emph{dual execution} and \emph{time-lock puzzles} to design a robust PVC-secure two-party protocol with \emph{low overhead} (depending on the deterrence factor). For instance, with a deterrence factor of $90\%$, our robust PVC-secure protocol incurs \emph{only additional ${\sim}10\%$ overhead} compared to the state-of-the-art PVC-secure protocol.
Given the stronger security guarantees with low overhead, our protocol is highly suitable for practical applications of secure two-party computation.
Zhenzhen Bao, Jinyu Lu, Yiran Yao, Liu Zhang
Théophile Wallez, Jonathan Protzenko, Karthikeyan Bhargavan
We propose a new framework, “Comparse”, that specifically tackles the security analysis of data formats in cryptographic protocols. Comparse forces the protocol analyst to systematically think about data formats, formalize them precisely, and show that they enjoy strong enough properties to guarantee the security of the protocol.
Our methodology is developed in three steps. First, we introduce a high-level cryptographic API that lifts the traditional game-based cryptographic assumptions over bitstrings to work over high-level messages, using formats. This allows us to derive the conditions that secure formats must obey in order for their usage to be secure. Second, equipped with these security criteria, we implement a framework for specifying and verifying secure formats in the F* proof assistant. Our approach is based on format combinators, which enable compositional and modular proofs. In many cases, we relieve the user of having to write those combinators by hand, using compile-time term synthesis via Meta-F*. Finally, we show that our F* implementation can replace the symbolic notion of message formats previously implemented in the DY* protocol analysis framework. Our newer, bit-level precise accounting of formats closes the modeling gap, and allows DY* to reason about concrete messages and identify protocol flaws that it was previously oblivious to.
We evaluate Comparse over several classic and real-world protocols. Our largest case studies use Comparse to formalize and provide security proofs for the formats used in TLS 1.3, as well as upcoming protocols like MLS and Compact TLS 1.3 (cTLS), providing confidence and feedback in the design of these protocols.
Dario Fiore, Dimitris Kolonelos, Paola de Perthuis
In this work, we put forward a new methodology to construct RBE schemes that support large users identities (i.e., arbitrary strings). Our main result is the first efficient pairing-based RBE for large identities. Prior to our work, the most efficient RBE is that of [Glaeser et al. ePrint'22] which only supports small identities. The only known RBE schemes with large identities are realized either through expensive non-black-box techniques (ciphertexts of 3.6 TB for 1000 users), or via a specialized lattice-based construction [Döttling et al. Eurocrypt'23] (ciphertexts of 2.4 GB). By unlocking the use of pairings for RBE with large identity space, we enable a further improvement of three orders of magnitude, as our ciphertexts for a system with 1000 users are $1.7$ MB.
The core technique of our approach is a novel use of cuckoo hashing in cryptography that can be of independent interest. We give two main applications. The first one is the aforementioned RBE methodology, where we use cuckoo hashing to compile an RBE with small identities into one for large identities. The second one is a way to convert any vector commitment scheme into a key-value map commitment. For instance, this leads to the first algebraic pairing-based key-value map commitments.
Min Zhang, Yu Chen, Chuanzhou Yao, Zhichao Wang
Furthermore, we show an application of our framework in designing ZKPs for composite statements, which contain both algebraic and non-algebraic statements. We give a generic construction of ZKPs for composite statements by combining Sigma protocols from VSS and ZKPs following MPC-in-the-head paradigm seamlessly via a technique of witness sharing reusing. Our construction has advantages of requiring no trusted setup, being public-coin and having a fast prover runtime. By instantiating our construction using Ligero++ (Bhadauria et al., CCS 2020), we obtain a new ZK protocol for composite statements, which achieves a new balance between running time and the proof size, thus resolving the open problem left by Backes et al. (PKC 2019). Concretely, the proof size is polylogarithmic to the circuit size and the number of public-key operations that both the prover and the verifier require is independent to the circuit size.
Yongcheng Song, Jiang Zhang, Xinyi Huang, Wei Wu
As an application, we show that the two rank-based cryptosystems submitted to the NIST PQC competition, namely, RQC and ROLLO, can be greatly improved by using the ideal variants of the $\ell$-RD problem and $\ell$-LRPC codes. Concretely, for 128-bit security, our RQC has total public key and ciphertext sizes of 2.5 KB, which is not only about 50% more compact than the original RQC, but also smaller than the NIST Round 4 code-based submissions HQC, BIKE, and Classic McEliece.
Shichen Wu, Zhiying Song, Puwen Wei, Peng Tang, Quan Yuan
David Balbás, Daniel Collins, Phillip Gajland
What can be proven about the security of the Sender Keys protocol, and how can we practically mitigate its shortcomings?
In addressing this question, we first introduce a novel security model to suit protocols like Sender Keys, deviating from conventional group key agreement-based abstractions. Our framework allows for a natural integration of two-party messaging within group messaging sessions that may be of independent interest. Leveraging this framework, we conduct the first formal analysis of the Sender Keys protocol, and prove it satisfies a weak notion of security. Towards improving security, we propose a series of efficient modifications to Sender Keys without imposing significant performance overhead. We combine these refinements into a new protocol that we call Sender Keys+, which may be of interest both in theory and practice.