IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
15 September 2022
Azam Soleimanian
Jiahui He, Kai Hu, Bart Preneel, Meiqin Wang
You Lyu, Shengli Liu, Shuai Han, Dawu Gu
We propose a generic construction of robust PPAKE from key encapsulation mechanism (KEM), digital signature (SIG), message authentication code (MAC), pseudo-random generator (PRG) and symmetric encryption (SE). By instantiating KEM, MAC, PRG from the DDH assumption and SIG from the CDH assumption, we obtain a specific robust PPAKE scheme in the standard model, which enjoys forward security for session keys, explicit authentication and forward privacy for user identities. Thanks to the robustness of our PPAKE, the number of broadcast messages per run and the computational complexity per user are constant, and in particular, independent of the number of users in the system.
14 September 2022
Each such event is expected to provide a forum discussing a specific topic of the broad cryptographic world (theory, practice, implementation, standardizations, etc.). The format of the event (e.g. workshop, tutorial, etc.) is up to the organizers.
Proposals for events should be submitted by email to the Eurocrypt 2023 workshop chair at eurocrypt2023workshops@iacr.org by September 30, 2022.
For more information, please visit: https://eurocrypt.iacr.org/2023/affiliated.php
Ulrich Haböck
Benjamin Dowling, Felix Günther, Alexandre Poirrier
In this paper, we propose a new method for performing continuous authentication during a secure messaging session, without the need for an out-of-band channel. Leveraging the users' long-term secrets, our Authentication Steps extension guarantees authenticity as long as long-term secrets are not compromised, strengthening Signal's post-compromise security. Our mechanism further allows to detect a potential compromise of long-term secrets after the fact via an out-of-band channel.
Our protocol comes with a novel, formal security definition capturing continuous authentication, a general construction for Signal-like protocols, and a security proof for the proposed instantiation. We further provide a prototype implementation which seamlessly integrates on top of the official Signal Java library, together with bandwidth and storage overhead benchmarks.
Karim Baghery, Navid Ghaedi Bardeh
Barbara Jiabao Benedikt, Marc Fischlin, Moritz Huppert
David Chaum, Richard T. Carback, Jeremy Clark, Chao Liu, Mahdi Nejadgholi, Bart Preneel, Alan T. Sherman, Mario Yaksetig, Zeyuan Yin, Filip Zagórski, Bingsheng Zhang
Anthony Hart
Jiamin Cui, Kai Hu, Meiqin Wang, Puwen Wei
In this paper, we extend the division property, a state-of-the-art framework for finding the upper bound of the algebraic degree over binary fields, to the scope of $\mathbb{F}_{2^n}$. It is a generic method to detect the algebraic degree for AO ciphers, even applicable to Feistel ciphers which have no better bounds than the trivial exponential one. In this general division property, our idea is to evaluate whether the polynomial representation of a block cipher contains some specific monomials. With a deep investigation of the arithmetical feature, we introduce the propagation rules of monomials for field-based operations, which can be efficiently modeled using the bit-vector theory of SMT. Then the new searching tool for degree estimation can be constructed due to the relationship between the algebraic degree and the exponents of monomials.
We apply our new framework to some important AO ciphers, including Feistel MiMC, GMiMC, and MiMC. For Feistel MiMC, we show that the algebraic degree grows significantly slower than the native exponential bound. For the first time, we present a secret-key higher-order differential distinguisher for up to 124 rounds, much better than the 83-round distinguisher for Feistel MiMC permutation proposed at CRYPTO 2020. We also exhibit a full-round zero-sum distinguisher with a data complexity of $2^{251}$. Our method can be further extended for the general Feistel structure with more branches and exhibit higher-order differential distinguishers against the practical instance of GMiMC for up to 50 rounds. For MiMC in SP-networks, our results correspond to the exact algebraic degree proved by Bouvier et al. We also point out that the number of rounds in MiMC's specification is not sufficient to guarantee the security against the higher-order differential attack for MiMC-like schemes with different exponents. The investigation of different exponents provides some guidance on the cipher design.
Matilda Backendal, Felix Günther, Kenneth G. Paterson
Hu Yupu, Dong Siyue, Wang Baocang, Liu Jun
In this paper we discuss the validity and the efficiency of reusable garbling scheme. We present the following three notes on the scheme.
(1) Reusable garbling scheme does not provide new applications, and it is still a one-time garbling scheme.
(2) Even reusable garbling scheme is taken as a one-time garbling scheme, sometimes it is not usable. More detailedly, it can only be used for Basic Scene 2, and cannot be used for Basic Scene 1. For example, it cannot be used for MPC.
(3) Even reusable garbling scheme is taken as a one-time garbling scheme used for Basic Scene 2, there is no evidence to show that its efficiency is better than a former one-time garbling scheme.
Aditya Hegde, Nishat Koti, Varsha Bhat Kukkala, Shravani Patil, Arpita Patra, Protik Paul
Our contributions are not only motivated by the practical viewpoint, but also consider the theoretical aspects of $\mathtt{FaF}$ security. We prove the necessity of semi-honest oblivious transfer for $\mathtt{FaF}$-secure protocols with optimal resiliency. On the practical side, we present QuadSquad, a ring-based 4PC protocol, which achieves fairness and GOD in the $\mathtt{FaF}$ model, with an optimal corruption of $1$ malicious and $1$ semi-honest party. QuadSquad is, to the best of our knowledge, the first practically efficient $\mathtt{FaF}$ secure protocol with optimal resiliency. Its performance is comparable to the state-of-the-art dishonest majority protocols while improving the security guarantee from abort to fairness and GOD. Further, QuadSquad elevates the security by tackling a stronger adversarial model over the state-of-the-art honest-majority protocols, while offering a comparable performance for the input-dependent computation. We corroborate these claims by benchmarking the performance of QuadSquad. We also consider the application of liquidity matching that deals with highly sensitive financial transaction data, where $\mathtt{FaF}$ security is apt. We design a range of $\mathtt{FaF}$ secure building blocks to securely realize liquidity matching as well as other popular applications such as privacy-preserving machine learning (PPML). Inclusion of these blocks makes QuadSquad a comprehensive framework.
Reo Eriguchi, Kaoru Kurosawa, Koji Nuida
Oana Ciobotaru, Fatemeh Shirazi, Alistair Stewart, Sergey Vasilyev
13 September 2022
University College Dublin
Closing date for applications:
Contact: The position is supervised by Asst. Prof. Dr. Madhusanka Liyanage (https://scholar.google.fi/citations?user=p1n0ioUAAAAJ&hl=en) and Asst. Prof. Dr. Shen Wang (https://scholar.google.com/citations?user=rPAOzIwAAAAJ&h).
The University of Adelaide, Australia
This is a fixed term (18 months) position with a flexible start date up to January 2023.
Apply at: https://careers.adelaide.edu.au/cw/en/job/510702
Closing date for applications:
Contact: Yuval Yarom yval(at)cs.adelaide.edu.au
J.P. Morgan Chase & Co.
The Cryptography Architect will be responsible for guiding how advanced and innovative cryptography is leveraged at JPMorgan Chase. As an experienced member of the Emerging Technologies Security group within the Cybersecurity & Technology Controls organization, you will interact with like-minded cryptographers and a group of passionate security engineers to work on concrete applications of advanced cryptography schemes. You will also have the opportunity to collaborate with other cryptographers on research projects.
The position requires strong academic knowledge as well as some industry experience in vetting and applying advanced cryptography schemes to secure complex IT infrastructure, customer-facing services, and sensitive customer and enterprise data.
Knowledge, experience, and capability required for the role include:
- Expertise in both mainstream encryption schemes and key exchange protocols as well as quantum-safe cryptography
- Strong familiarity with NIST post-quantum cryptography standardization & migration efforts
- Hands-on experience with implementing, testing and deploying advanced cryptographic schemes
- Familiarity with NIST Cryptographic Standards and Guidelines
- Proficiency in multiple programming languages, e.g., Java, C#, JavaScript, C/C++
- Ability to convey complex concepts in a clear & concise manner to a wide range of audience
- Proven track record in publishing papers (academia, whitepaper, position paper etc.)
- Proven track record in working with diverse teams to achieve goals
- Driving enterprise-wide transformative security technology initiatives
- PhD (preferred) or MS in computer science
Closing date for applications:
Contact: Hubert Le Van Gong, Ph.D. | Managing Director | Cybersecurity & Technology Controls
More information: https://jpmc.fa.oraclecloud.com/hcmUI/CandidateExperience/en/sites/CX_1001/job/210337824/?utm_medium=jobshare
J.P. Morgan Chase & Co.
The Applied Cryptography Architect will be responsible for leveraging innovative cryptography at JPMorgan Chase. As a member of the Emerging Technologies Security group within the Cybersecurity & Technology Controls organization, you will work alongside cryptographers and a group of passionate security engineers to solve complex security problems and support the deployment of cryptography-based solutions.
The position requires extensive knowledge and industry experience in combining cryptography and security best-practices to secure complex IT infrastructure, customer-facing services, and sensitive customer and enterprise data.
Knowledge, experience, and capability required for the role include:
- Expertise in applying mainstream cryptographic primitives, including digital signatures, public-key ciphers, block ciphers Good understanding and hands-on experience of network security protocols (TLS etc.)
- Familiarity with NIST post-quantum cryptography standardization & migration efforts
- Security solution development utilizing cryptographic agility principles and elements
- Proficiency in multiple programming languages, e.g., Java, C#, JavaScript, C/C++
- Hands-on data protection solution development utilizing industry standard security protocol and best-practices
- Application knowledge of public key infrastructure (PKI) and digital certificates (e.g., X.509)
- Ability to convey complex concepts and ideas in a clear and concise manner to a wide range of audience
- Proven track record in working with diverse teams to achieve goals
- Driving enterprise-wide transformative security technology initiatives
- MS (preferred) or BS in computer science
Closing date for applications:
Contact: Hubert Le Van Gong, Ph.D. | Managing Director | Cybersecurity & Technology Controls
More information: https://jpmc.fa.oraclecloud.com/hcmUI/CandidateExperience/en/sites/CX_1001/job/210337262/?utm_medium=jobshare