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20 February 2022
Gal Arnon, Alessandro Chiesa, Eylon Yogev
ePrint ReportIn this paper, we establish hardness of approximation for SCSPs based on interactive proofs. For $k \leq O(\log n)$, we prove that it is $AM[k]$-hard to approximate, to within a constant, the value of SCSPs with $k$ alternations and constant arity. Before, this was known only for $k = O(1)$.
Furthermore, we introduce a natural class of $k$-round interactive proofs, denoted $IR[k]$ (for \emph{interactive reducibility}), and show that several protocols (e.g., the sumcheck protocol) are in $IR[k]$. Using this notion, we extend our inapproximability to all values of $k$: we show that for every $k$, approximating an SCSP instance with $O(k)$ alternations and constant arity is $IR[k]$-hard.
While hardness of approximation for CSPs is achieved by constructing suitable PCPs, our results for SCSPs are achieved by constructing suitable IOPs (interactive oracle proofs). We show that every language in $AM[k \leq O(\log n)]$ or in $IR[k]$ has an $O(k)$-round IOP whose verifier has \emph{constant} query complexity (\emph{regardless} of the number of rounds $k$). In particular, we derive a ``sumcheck protocol'' whose verifier reads $O(1)$ bits from the entire interaction transcript.
Benny Applebaum, Eliran Kachlon, Arpita Patra
ePrint ReportAs our main contribution, we show that every efficiently-computable relation can be realized by a VRS with an optimal round complexity of two rounds where the first round is input-independent (offline round). The protocol achieves full UC-security against an active adversary that is allowed to corrupt any $t$-subset of the parties that may include the client together with some of the verifiers. For a small (logarithmic) number of parties, we achieve an optimal resiliency threshold of $t=0.5(k+1)$, and for a large (polynomial) number of parties, we achieve an almost-optimal resiliency threshold of $t=0.5(k+1)(1-\epsilon)$ for an arbitrarily small constant $\epsilon>0$. Both protocols can be based on sub-exponentially hard injective one-way functions. If the parties have an access to a collision resistance hash function, we can derive \emph{statistical everlasting security}, i.e., the protocols are secure against adversaries that are computationally bounded during the protocol execution and become computationally unbounded after the protocol execution.
\smallskip Previous 2-round solutions achieve smaller resiliency thresholds and weaker security notions regardless of the underlying assumptions. As a special case, our protocols give rise to 2-round offline/online constructions of multi-verifier zero-knowledge proofs (MVZK). Such constructions were previously obtained under the same type of assumptions that are needed for non-interactive zero-knowledge proofs (NIZK), i.e., public-key assumptions or random-oracle type assumptions (Abe et al., Asiacrypt 2002; Groth and Ostrovsky, Crypto 2007; Boneh et al., Crypto 2019; Yang, and Wang, Eprint 2022). Our work shows, for the first time, that in the presence of an honest majority these assumptions can be replaced with more conservative ``Minicrypt''-type assumptions like injective one-way functions and collision-resistance hash functions. Indeed, our MVZK protocols provide a round-efficient substitute for NIZK in settings where honest-majority is present. Additional applications are also presented.
Thien Duc Nguyen, Markus Miettinen, Alexandra Dmitrienko, Ahmad-Reza Sadeghi, Ivan Visconti
ePrint ReportDurba Chatterjee, Debdeep Mukhopadhyay, Aritra Hazra
ePrint ReportYunzhou Yan, Yu Xia, Srinivas Devadas
ePrint ReportWith n parties, Shanrang tolerates n/4 Byzantine faults and maintains liveness as long as the messages are delivered. In contrast to prior work, Shanrang makes no assumptions on the network latency. Designing an asynchronous protocol is challenging because it is impossible to distinguish an adversary sending no messages from an honest party whose messages have not arrived yet. We evaluated Shanrang on geographically distributed machines and we found Shanrang achieved 200 seconds for handing off between 2 committees of 41 parties. Shanrang requires O(λn3 log n) messages and runs in expected O(log n) rounds for every handoff. To show Shanrang is robust even in a harsh network environ- ment, we test Shanrang on the Tor network and it shows robust performance.
James Lovejoy, Cory Fields, Madars Virza, Tyler Frederick, David Urness, Kevin Karwaski, Anders Brownworth, Neha Narula
ePrint ReportThis paper presents Hamilton, a flexible transaction processor design that supports a range of models for a CBDC and minimizes data storage in the core transaction processor by storing unspent funds as opaque hashes. Hamilton supports users custodying their own funds or custody provided by financial intermediaries.
We describe and evaluate two implementations: the atomizer architecture which provides a globally ordered history of transactions but is limited in throughput (170,000 transactions per second), and the 2PC architecture that scales peak throughput almost linearly with resources (up to a measured throughput of 1.7M transactions per second) but does not provide a globally ordered list of transactions.
We released our two architectures under the MIT open source license at https://github.com/mit-dci/opencbdc-tx.
Anamaria Costache, Benjamin R. Curtis, Erin Hales, Sean Murphy, Tabitha Ogilvie, Rachel Player
ePrint ReportEaswar Vivek Mangipudi, Aniket Kate
ePrint Report16 February 2022
Karlsruhe Institute of Technology (KIT), Germany
Job PostingYou will be a member of the KASTEL Security Research Labs (https://zentrum.kastel.kit.edu) and the Topic "Engineering Secure Systems" of the Helmholtz Association. Your research is dealing with cryptographic protocols for privacy-preserving computations, e.g., applied to mobility or production systems. It will result in both theoretical security concepts (protocol designs, security proofs, etc.) and their practical implementation (e.g., a demonstrator) for some application domain. The contract will initially be limited to 1 year, but can be extended.
If you are interested, please send an email including your CV and a list of publications to andy.rupp@rub.de. Applications will be reviewed continuously until the positions are filled.
Closing date for applications:
Contact: Andy Rupp (andy.rupp@rub.de)
Qualcomm Sophia Antipolis (France)
Job PostingSnapdragon processors are used in different types of devices ranging from mobile phones to televisions, cars, ultra-book laptops etc. Our processors are designed to meet security requirements ranging from content protection to enterprise security, using virtualization, HW security enclaves, factory key provisioning, and secure updates.
In this position you will perform the following tasks:
- Define HW crypto security requirements (functional, performance, security etc)
- Define HW/SW partitioning to address next challenges in cryptography such as PQC and Crypto Agility
- Define crypto and HW blocks that contribute to the overall SoC Security Architecture
- Design of mechanisms thwarting side channel attacks
- Monitor evaluation of crypto IP resistance and robustness
- Competitive analysis of security IPs and features
- Investigate future/roadmap security related technologies,
- Participation in academic conference and industrial/research security working groups.
- Cryptographic primitives, cryptographic protocols and their implementation
- Design of HW/SW security blocks such as HW cryptographic engines
- HW/SW threat analysis, security analysis or/and risk analysis
- Smart Card and secure HW technologies
- Security certifications: process and requirements.
- Academic and industry research (publications, conferences)
- Leadership & management background
- Excellent communication and teamwork skills are required
Closing date for applications:
Contact: Nicolas Courtois
14 February 2022
Port Dickson, Malaysia, 26 July - 28 July 2022
Event CalendarSubmission deadline: 15 March 2022
Notification: 25 May 2022
Virtual event, Anywhere on Earth, 10 July - 16 July 2022
Event CalendarSubmission deadline: 1 April 2022
Notification: 15 May 2022
Ikebukuro, Japan, 31 August - 2 September 2022
Event CalendarSubmission deadline: 26 March 2022
Notification: 30 May 2022
National Research Council Canada, Ottawa, Ontario
Job PostingClosing date for applications:
Contact: Human Resources at: NRC.NRCHiring-EmbaucheCNRC.CNRC@nrc-cnrc.gc.ca
More information: https://recruitment-recrutement.nrc-cnrc.gc.ca/job-invite/15641
Nanyang Technological University, Singapore
Job Posting- tool aided cryptanalysis, such as MILP, CP, STP, and SAT
- machine learning aided cryptanalysis and designs
- privacy-preserving friendly symmetric-key designs
- quantum cryptanalysis
- provable security
- cryptanalysis against SHA-2, SHA-3, and AES
- threshold cryptography
Closing date for applications:
Contact: Jian Guo, guojian@ntu.edu.sg, with subject [IACR-CATF]
More information: https://team.crypto.sg
Mohammed VI Polytechnic University, Morocco
Job PostingThe project is jointly conducted between Mohammed VI Polytechnic University, Morocco, and EPFL Switzerland.
To apply, please send your cv with your list of publications.
Closing date for applications:
Contact: Mehdi Amhoud, email : elmehdi.amhoud(at)um6p.ma
Protocol Labs
Job PostingClosing date for applications:
Contact: Apply here- https://boards.greenhouse.io/protocollabs/jobs/4283969004
More information: https://boards.greenhouse.io/protocollabs/jobs/4283969004
13 February 2022
CRYPTO
Instructions for authors and the link to submission server can be found here https://crypto.iacr.org/2022/papersubmission.php.