IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
01 October 2022
CryptoExperts
The ambition of CryptoExperts is to develop innovative technologies in cryptography to meet the emerging needs of the security industry. This ambition is reflected through a team of multi-experts in cryptography and engineers endowed with a particular taste for research, innovation and practical applications.
As software engineer you will be working alongside a team of cryptographers to address the needs of CryptoExperts’ customers in terms of software development and evaluation. You will contribute to the internal R&D effort of the company, notably in terms of design and implementation of
- cryptographic libraries targeting high efficiency and high security in constrained environments (e.g. embedded systems),
- a framework for the design and implementation of white-box cryptography components (compilation and obfuscation).
Please refer to the full job offer for complete information.
Closing date for applications:
Contact: Matthieu Rivain
More information: https://www.cryptoexperts.com/job-offer-software-engineer.pdf
CryptoExperts
The ambition of CryptoExperts is to develop innovative technologies in cryptography to meet the emerging needs of the security industry. This ambition is reflected through a team of multi-experts in cryptography and engineers endowed with a particular taste for research, innovation and practical applications.
As a cryptography expert, you will contribute to R&D and consulting missions for various customers, including
- security assessments for systems/applications that involve cryptography,
- development of secure and optimized cryptographic libraries,
- feasibility study and the tailor-made design of specific cryptographic solutions.
You will also take part to various research projects of the company on topics such as homomorphic encryption, white-box cryptography, post-quantum cryptography, secure cryptographic implementations, security proofs against side-channel attacks, zero-knowledge proofs.
Please refer to the full job offer for complete information.
Closing date for applications:
Contact: Matthieu Rivain
More information: https://www.cryptoexperts.com/job-offer-cryptography-expert.pdf
30 September 2022
Theodoros Kapourniotis, Elham Kashefi, Dominik Leichtle, Luka Music, Harold Ollivier
To this end, we establish a fundamental correspondence between error-detection and verification and provide sufficient conditions to both achieve security in the Abstract Cryptography framework and optimise resource overheads of all known VBQC-based protocols. As a direct application, we demonstrate how to systematise the search for new efficient and robust verification protocols for $\mathsf{BQP}$ computations. While we have chosen Measurement-Based Quantum Computing (MBQC) as the working model for the presentation of our results, one could expand the domain of applicability of our framework via direct known translation between the circuit model and MBQC.
Hanno Becker, Fabien Klein
Bishakh Chandra Ghosh, Sikhar Patranabis, Dhinakaran Vinayagamurthy, Venkatraman Ramakrishna, Krishnasuri Narayanam, Sandip Chakraborty
Hu Yupu, Dong Siyue, Wang Baocang, Dong Xingting
In this short paper we point out that Lin16/Lin17 schemes are invalid. More detailedly, they cannot achieve reusability, therefore they are not true IO schemes, but rather garbling schemes which are one-time schemes.
arash mirzaei, Amin Sakzad, Jiangshan Yu, Ron Steinfeld
Ke Zhong, Yiping Ma, Yifeng Mao, Sebastian Angel
Nir Drucker, Guy Moshkowich, Tomer Pelleg, Hayim Shaul
We show that by treating step functions as “clean-up” utilities and by leveraging the SIMD capabilities of CKKS, we can extend the homomorphic encryption toolbox with efficient tools. These tools use CKKS to run unbounded circuits that operate over binary and small-integer elements and even combine these circuits with fixed-point real numbers circuits. We demonstrate the results using the Turing-complete Conway’s Game of Life. In our evaluation, for boards of size 128x128, these tools achieved an order of magnitude faster latency than previous implementations using other HE schemes. We argue and demonstrate that for large enough real-world inputs, performing binary circuits over CKKS, while considering it as an “exact” scheme, results in comparable or even better performance than using other schemes tailored for similar inputs.
Simone Dutto, Davide Margaria, Carlo Sanna, Andrea Vesco
Constantin Blokh, Nikolaos Makriyannis, Udi Peled
** The preprocessing phase for calculating preprocessed data for future signatures is lightweight and non-interactive; it consists of each party sending a single independently-generated short message per future signature per online party (approx.~300B for typical choice of parameters).
** The signing phase is asymmetric in the following sense; to calculate the signature, it is enough for the offline party to receive a single short message from the online ``world'' (approx.~300B).
We note that all previous ECDSA protocols require many rounds of interaction between all parties, and thus all previous protocols require extensive ``interactive time'' from the offline party. In contrast, our protocol requires minimal involvement from the offline party, and it is thus ideal for MPC-based cold storage.
Our main technical innovation for achieving the above is twofold: First, building on recent protocols, we design a two-party protocol that we non-generically compile into a highly efficient $(n+1)$-party protocol. Second, we present a new batching technique for proving in zero-knowledge that the plaintext values of practically any number of Paillier ciphertexts lie in a given range. The cost of the resulting (batched) proof is very close to the cost of the underlying single-instance proof of MacKenzie and Reiter (CRYPTO'01, IJIS'04). We prove security in the UC framework, in the global random oracle model, assuming Strong RSA, semantic security of Paillier encryption, DDH, and enhanced existential unforgeability of ECDSA; these assumptions are widely used in the threshold-ECDSA literature and many commercially-available MPC-based wallets.
Arash Mirzaei, Amin Sakzad, Jiangshan Yu, Ron Steinfeld
This paper introduces Daric, a payment channel with unlimited lifetime for Bitcoin that achieves optimal storage and bounded closure. Moreover, Daric implements a punishment mechanism and simultaneously avoids the methods other schemes commonly use to enable punishment: 1) state duplication which leads to exponential increase in the number of transactions with the number of applications on top of each other or 2) dedicated design of adaptor signatures which introduces compatibility issues with BLS or most post-quantum resistant digital signatures. We also formalise Daric and prove its security in the Universal Composability model.
29 September 2022
Elaine Shi, Hao Chung, Ke Wu
In this work, we explore what new models and meaningful relaxations can allow us to circumvent the impossibility results of Chung and Shi. Besides today’s model that does not employ cryptography, we introduce a new MPC-assisted model where the TFM is implemented by a joint multi-party computation (MPC) protocol among the miners. We prove several feasibility and infeasibility results for achieving strict and approximate incentive compatibility, respectively, in the plain model as well as the MPC-assisted model. We show that while cryptography is not a panacea, it indeed allows us to overcome some impossibility results pertaining to the plain model, leading to non-trivial mechanisms with useful guarantees that are otherwise impossible in the plain model. Our work is also the first to characterize the mathematical landscape of transaction fee mechanism design under approximate incentive compatibility, as well as in a cryptography-assisted model.
Xavier Bultel, Ashley Fraser, Elizabeth A. Quaglia
Moni Naor, Noa Oved
Liliya Akhmetzyanova, Evgeny Alekseev, Alexandra Babueva, Andrey Bozhko, Stanislav Smyshlyaev
The registration site is now open: https://tcc.iacr.org/2022/registration.php
28 September 2022
Zeyuan Yin, Bingsheng Zhang, Jingzhong Xu, Kaiyu Lu, Kui Ren
David Jacquemin, Ahmet Can Mert, Sujoy Sinha Roy
Yuval Ishai, Dakshita Khurana, Amit Sahai, Akshayaram Srinivasan
\begin{enumerate} \item {\bf Two-party protocol.} We give a (two-round) {\it two-sided NISC} protocol that makes black-box use of two-round (malicious-secure) OT in the CRS model. In contrast to the standard setting of non-interactive secure computation (NISC), two-sided NISC allows communication from both parties in each round and delivers the output to both parties at the end of the protocol. Prior black-box constructions of two-sided NISC relied on idealized setup assumptions such as OT correlations, or were proven secure in the random oracle model. \item {\bf Multiparty protocol.} We give a three-round secure multiparty computation protocol for an arbitrary number of parties making black-box use of a two-round OT in the CRS model. The round optimality of this construction follows from a black-box impossibility proof of Applebaum et al. (ITCS 2020). Prior constructions either required the use of random oracles, or were based on two-round malicious-secure OT protocols that satisfied additional security properties. \end{enumerate}