IACR News
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28 July 2022
Oguzhan Ersoy, Pedro Moreno-Sanchez, Stefanie Roos
ePrint ReportWe introduce Bailout, the first protocol that allows intermediary parties in a multi-hop payment to unlock their coins before the payment completes by re-routing the payment over an alternative path. We achieve this by creating a circular payment route starting from the intermediary party in the opposite direction of the original payment. Once the circular payment is locked, both payments are canceled for the intermediary party, which frees the coins of the corresponding channels. This way, we create an alternative route for the ongoing multi-hop payment without involving the sender or receiver. The parties on the alternative path are incentivized to participate through fees.
We prove the security of our protocol in the Universal Composability (UC) framework. Furthermore, we evaluate the utility of our protocol using a real-world Lightning Network snapshot. Bailouts may fail due to insufficient balance in alternative paths used for re-routing. We find that attempts of a node to bailout typically succeed with a probability of more than 94% if at least one alternative path exists.
Jim Posen, Assimakis A. Kattis
ePrint ReportJunhao Huang, Jipeng Zhang, Haosong Zhao, Zhe Liu, Ray C. C. Cheung, Çetin Kaya Koç, Donglong Chen
ePrint ReportAndrea Caforio, Daniel Collins, Subhadeep Banik, Francesco Regazzoni
ePrint ReportIn this paper, we fill this gap regarding efficient field arithmetic in bit- serial circuits, and propose a lightweight circuit for GIFT-COFB that occupies less than 1500 GE, making it the to-date most area-efficient implementation of this construction. In a second step, we demonstrate how the additional operations in the mode can be executed concurrently with GIFT itself so that the total latency is significantly reduced whilst incurring only a modest area increase. Finally, we propose a first-order threshold implementation of GIFT-COFB, which we experimentally verify resists first-order side-channel analysis.
Harishma Boyapally, Sikhar Patranabis, Debdeep Mukhopadhyay
ePrint Report24 July 2022
Kolkata, India, 11 December - 14 December 2022
Event CalendarSubmission deadline: 1 September 2022
Notification: 15 October 2022
TU Darmstadt
Job PostingTopics of particular interest include (but are not limited to):
- Leakage/tamper resilient cryptography
- Cryptography for blockchains and cryptocurrencies
- Multiparty computation & threshold cryptography
- Completed Master's degree (or equivalent) with excellent grades in computer science, mathematics or a similar area.
- Strong mathematical and/or algorithmic/theoretical CS background
- Good knowledge of cryptography. Knowledge in concepts of provable security is a plus.
- Fluent written and verbal communication skills in English
Review of applications starts immediately until the position is filled. For further information please visit: https://www.informatik.tu-darmstadt.de/cac/cac/index.en.jsp
Closing date for applications:
Contact: Sebastian Faust (office.cac@cysec.de)
Huawei German Research Center, Munich
Job PostingThe ideal candidate would have background in probabilistic reasoning and logic or formal methods and understanding of security.
The position is connected to a new EU Project starting in September 2022 on Security and Trust in Connected, Cooperative, Automated Mobility (CCAM). The PhD candidate will be funded by the project and PhD topic will be connected directly to the research inside this project. Goal is to complete it in 3 years.
Research Topic
- Perform research and develop new solutions for Trust Management in the Next-Generation CCAM technologies.
- Contribute to new mechanisms for assessing dynamic trust relationship based on Zero Trust and Subjective Logic.
- Define a trust model and trust reasoning framework based on which involved entities can establish trust for cooperatively executing safety-critical functions.
- Contribute to the research and development of technologies in the upcoming domain of Connected, Cooperative and Automated Mobility (CCAM).
- Being involved in international initiatives including industry groups such as 5GAA, Gaia-X, DIF and Horizon Europe research projects.
- Completed master studies (or equivalent) in computer science, information technology, electrical engineering, or mathematics;
- Background in probabilistic reasoning and logic or formal methods
- Exposure and understanding of data protection and security development technologies;
- Good programming skill;
- Fluent in English;
Closing date for applications:
Contact: Ioannis Krontiris (ioannis.krontiris@huawei.com)
More information: https://huaweiresearchcentergermanyaustria.teamtailor.com/jobs/1732783-phd-student-security-trust-connected-cooperative-automated-mobility-m-f-d
23 July 2022
Anubhab Baksi, Arghya Bhattacharjee, Jakub Breier, Takanori Isobe, Mridul Nandi
ePrint ReportIn this work, we revisit the work by Peyrin and Wang in a greater depth. We discuss the relevant aspects with more clarity, thereby addressing some of the important issues connected to a backdoor construction. The main contribution, however, comes as a new proof-of-concept block cipher with an innate backdoor, named ZUGZWANG. Unlike Malicious, which needs new/experimental concepts like partially non-linear layer; our cipher entirely relies on concepts which are well-established for decades (such as, using an one-way function as a Feistel cipher's state-update), and also offers quite a few advantages over Malicious (easy to visualise, succeeds with probability 1, and so on). Having known the secret backdoor entry, one can recover the secret key with only 1 plaintext query to our cipher; but it is secure otherwise. As the icing on the cake, we show the provable security claims for our cipher.
Michael Fahr Jr., Hunter Kippen, Andrew Kwong, Thinh Dang, Jacob Lichtinger, Dana Dachman-Soled, Daniel Genkin, Alexander Nelson, Ray Perlner, Arkady Yerukhimovich, Daniel Apon
ePrint ReportThen, we perform a decryption failure attack, using a variety of publicly-accessible supercomputing resources running on the order of only 200,000 core-hours. We delicately attenuate the decryption failure rate to ensure that the adversary's attack succeeds practically, but so honest users cannot easily detect the manipulation.
Achieving this public key "poisoning" requires an extreme engineering effort, as FrodoKEM's KeyGen runs on the order of 8 milliseconds. (Prior Rowhammer-assisted attacks against cryptography require as long as 8 hours of persistent access.) In order to handle this real-world timing condition, we require a wide variety of prior and brand new, low-level engineering techniques, including e.g. memory massaging algorithms -- i.e. "Feng Shui" -- and a precisely-targeted performance degradation attack on the extendable output function SHAKE.
We explore the applicability of our techniques to other lattice-based KEMs in the NIST PQC Round 3 candidate-pool, e.g. Kyber, Saber, etc, as well as the difficulties that arise in the various settings. To conclude, we discuss various simple countermeasures to protect implementations against this, and similar, attacks.
Jiajun Du, Zhonghui Ge, Yu Long, Zhen Liu, Shifeng Sun, Xian Xu, Dawu Gu
ePrint ReportIn this paper, we propose MixCT, a generic protocol that provides the mixing service for confidential payment systems built from homomorphic commitment in the account-based model. We formally define the security goals including safety and availability, and prove that our generic construction satisfies them. Furthermore, we provide an efficient instantiation of MixCT by the Pedersen commitment and the one-out-of-many proof. The evaluation results show that MixCT introduces a small cost for its users while being highly compatible with the underlying confidential blockchain.
Birenjith Sasidharan, Emanuele Viterbo
ePrint ReportAlexandra Henzinger, Matthew M. Hong, Henry Corrigan-Gibbs, Sarah Meiklejohn, Vinod Vaikuntanathan
ePrint ReportStephane Lemieux
ePrint ReportSteven Lambregts, Huanhuan Chen, Jianting Ning, Kaitai Liang
ePrint ReportTahoura Mosavirik, Patrick Schaumont, Shahin Tajik
ePrint ReportMarco Calderini, Riccardo Longo, Massimiliano Sala, Irene Villa
ePrint Report21 July 2022
Lucerne University of Applied Sciences and Arts
Job PostingCandidates should have a strong background in IT security and cryptography and/or good software engineering skills; knowledge in quantum information is advantageous. Both junior and more senior candidates are considered. For junior candidates, there exists the possibility to combine the employment with enrollment in a study-programm towards a PhD or a Master of Science in Engineering (MSE).
Closing date for applications:
Contact: Please apply online via the links provided above. For any further Information contact Prof. Dr. Esther Hänggi, esther.haenggi@hslu.ch
More information: https://recruitingapp-2678.umantis.com/Vacancies/2466/Description/1
University of Surrey
Job PostingThis post offers an exciting opportunity for an appointment in the Secure Systems group. Suitable areas of expertise that complement and extend strengths of the group include (but are not limited to): software security, program analysis, formal verification of software/systems, practical system security, trusted systems, distributed systems, complex systems and networks, as well as the interface between security and machine learning.
Candidates to the post should have a PhD in a relevant subject or equivalent professional experience. An ability to secure research funding and produce high quality outputs and manage research projects and supervise research students is also required. It is expected that the post-holder will also contribute to high quality teaching in cyber security and fundamental topics in computer science at undergraduate and post-graduate level and to supervise undergraduate projects and dissertations.
The University and the Department specifically are committed to building a culturally diverse organisation and strongly encourages applications from female and minority candidates. The Department of Computer Science was awarded a Bronze Athena SWAN award, in recognition of our commitment to equality and diversity.
The University of Surrey is committed to providing an inclusive environment that offers equal opportunities for all. We place great value on diversity and are seeking to increase the diversity within our community. Therefore, we particularly encourage applications from under-represented groups, such as people from Black, Asian and minority ethnic groups and people with disabilities.
Closing date for applications:
Contact: Professor Steve Schneider
s.schneider@surrey.ac.uk
More information: https://jobs.surrey.ac.uk/vacancy.aspx?ref=045822
20 July 2022
Huijia Lin, Tianren Liu
ePrint ReportIn this work, we improve the simplicity and efficiency of two-round MPC in the setting with dishonest majority and malicious security. Our protocols make use of the Random Oracle (RO) and a generalization of the Oblivious Linear Evaluation (OLE) correlated randomness, called tensor OLE, over a finite field $\mathbb{F}$, and achieve the following:
- MPC for Boolean Circuits: Our two-round, maliciously secure MPC protocols for computing Boolean circuits, has overall (asymptotic) computational cost $O(S\cdot n^3 \cdot \log |\mathbb{F}|)$, where $S$ is the size of the circuit computed, $n$ the number of parties, and $\mathbb{F}$ a field of characteristic two. The protocols also make black-box calls to a Pseudo-Random Function (PRF).
- MPC for Arithmetic Branching Programs (ABPs): Our two-round, information theoretically and maliciously secure protocols for computing ABPs over a general field $\mathbb{F}$ has overall computational cost $O(S^{1.5}\cdot n^3\cdot \log |\mathbb{F}|)$, where $S$ is the size of ABP computed.
Both protocols achieve security levels inverse proportional to the size of the field $|\mathbb{F}|$.
Our construction is built upon the simple two-round MPC protocols of [Lin-Liu-Wee TCC'20], which are only semi-honest secure. Our main technical contribution lies in ensuring malicious security using simple and lightweight checks, which incur only a constant overhead over the complexity of the protocols by Lin, Liu, and Wee. In particular, in the case of computing Boolean circuits, our malicious MPC protocols have the same complexity (up to a constant overhead) as (insecurely) computing Yao's garbled circuits in a distributed fashion.
Finally, as an additional contribution, we show how to efficiently generate tensor OLE correlation in fields of characteristic two using OT.