IACR News
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10 January 2022
CryptoExperts, Paris, France
Job PostingCryptoExperts develops and maintains a white-box cryptography technology which aims at producing white-box cryptography software components secure against beyond-state-of-the-art attacks.
We are looking for a candidate who will take part to the design and implementation effort of CryptoExperts’ white-box cryptography technology.
The complete job offer is available here: https://www.cryptoexperts.com/job-offer-wbc.pdf
Closing date for applications:
Contact: To apply please write to jobs@cryptoexperts.com with a short description of your profile, story and motivation, your CV, and (optionally) recommendation from (former) co-workers.
More information: https://www.cryptoexperts.com/job-offer-wbc.pdf
Norwegian University of Sciennce and Technology (NTNU), Dep. of Inf. Security and Comm. Technology
Job PostingRequired qualifications: You must have the qualifications required for the position of associate professor in the field of Cyptology, as outlined:
A. Your PhD, or comparable academic work, must be within the field of cryptology (or a comparable relevant field), of particular interest are candidates with a documented acadmic track record within one or several of the following topics: A1. Design and analysis of post-quantum cryptographic primitives; A2. Design and analysis of post-quantum cryptographic protocols; A3. Lightweight cryptography; A4. Blockchain technologies; A5. Cryptography and Privacy; A6. Homomorphic encryption; A7. Secure Cryptographic Hardware, Side Channels Security (attacks and resistance); A8. Cryptology and Biometrics; A9. Cryptology and Software Security (Secure Operating Systems).
B. Relevant academic fields include mathematics, computer science and communication technology. If you can document that you are in the final stages of your PhD studies, your application may also be considered.
C. Good written and oral English language skills.
More information about the position and the whole application process should be completed via the initial Jobbnorge link and web page
Closing date for applications:
Contact: Professor Danilo Gligoroski, e-mail danilo.gligoroski@ntnu.no
More information: https://www.jobbnorge.no/en/available-jobs/job/216381/associate-professor-in-cryptology
Amit Choudhari, Sylvain Guilley, Khaled Karray
ePrint ReportWe performed a feature-wise comparison with the existing state of the art solutions. CRYScanner includes additional features, preserving the capabilities of both static and dynamic analysis tools. We also show the detection of potential vulnerabilities in the several sample codes found online.
Elette Boyle, Itai Dinur, Niv Gilboa, Yuval Ishai , Nathan Keller, Ohad Klein
ePrint ReportNear-optimal LPHS via Distributed Discrete Log: We establish a general two-way connection between LPHS and algorithms for distributed discrete logarithm in the generic group model. Using such an algorithm of Dinur et al. (Crypto 2018), we get LPHS with near-optimal error of $\delta=\tilde O(1/d^2)$. This gives an unusual example for the usefulness of group-based cryptography in a post-quantum world. We extend the positive result to non-cyclic and worst-case variants of LPHS.
Multidimensional LPHS: We obtain positive and negative results for a multidimensional extension of LPHS, making progress towards an optimal 2-dimensional LPHS.
Applications: We demonstrate the usefulness of LPHS by presenting cryptographic and algorithmic applications. In particular, we apply multidimensional LPHS to obtain an efficient "packed" implementation of homomorphic secret sharing and a sublinear-time implementation of location-sensitive encryption whose decryption requires a significantly overlapping view.
Bingyong Guo, Yuan Lu, Zhenliang Lu, Qiang Tang, Jing Xu, Zhenfeng Zhang
ePrint ReportDespite those efforts, asynchronous BFT protocols remain to be slow, and in particular, the latency is still quite large. There are two reasons contributing to the inferior performance: (1) the reliable broadcast (RBC) protocols still incur substantial costs; (2) the MVBA protocols are quite complicated and heavy, and all existing constructions need dozens of rounds and take the majority of he overall latency.
We first present a new construction of asynchronous BFT that replaces RBC instance with a cheaper broadcast component. It not only reduces the $O(n^3)$ message complexity incurred by $n$ RBCs to $O(n^2)$, but also saves up to 67% communications (in the presence of a fair network scheduler). Moreover, our technical core is a new MVBA protocol, Speeding MVBA, which is concretely more efficient than all existing MVBAs. It requires only 6 rounds in the best case and expected 12 rounds in the worst case (by contrast, several dozens of rounds in the MVBA from Cachin et al. [12] and the recent Dumbo-MVBA [32], and around 20 rounds in the MVBA from Abraham et al. [4]). Our new technique of the construction might be of independent interests.
We implemented Speeding Dumbo and did extensive tests among up to 150 EC2 t2.medium instances evenly allocated in 15 AWS regions across the globe. The experimental results show that Speeding Dumbo reduces the latency to about a half of Dumbo's, and also doubles the throughput of Dumbo, through all system scales from 4 nodes to 150 nodes. We also did tests to benchmark individual components such as the broadcasts and the MVBA protocols, which may be of interests for future improvements.
Andrada-Teodora Ciulei, Marian-Codrin Crețu, Emil Simion
ePrint ReportMostafizar Rahman, Dhiman Saha, Goutam Paul
ePrint Report08 January 2022
Jean-Philippe Bossuat, Juan Ramón Troncoso-Pastoriza, Jean-Pierre Hubaux
ePrint ReportWe present a bootstrapping procedure for the CKKS scheme that combines both dense and sparse secrets. Our construction enables the use of parameters for which the homomorphic capacity is based on a dense secret, yet with a bootstrapping complexity that remains the one of a sparse secret and with a large security margin. Moreover, this also enables us to easily parameterize the bootstrapping circuit so that it has a negligible failure probability that, to the best of our knowledge, has never been achieved for the CKKS scheme. When using the parameters of previous works, our bootstrapping procedures enables a faster procedure with an increased precision and lower failure probability. For example we are able to bootstrapp a plaintext of $\mathbb{C}^{32768}$ in 20.2 sec, with 32.11 bits of precision, 285 bits of modulus remaining, a failure probability of $2^{-138.7}$ and 128 bit security.
Nicolai Müller, David Knichel, Pascal Sasdrich, Amir Moradi
ePrint ReportXiuju Huang, Jiashuo Song , Zichen Li
ePrint ReportSisi Duan, Haibin Zhang, Boxin Zhao
ePrint ReportWe show that WaterBear and WaterBear-QS are efficient under both failure-free and failure scenarios, achieving comparable performance to the state-of-the-art asynchronous BFT protocols. In particular, our failure case evaluation is thus far the most comprehensive evaluation for asynchronous BFT settings.
Sisi Duan, Haibin Zhang
ePrint ReportFukang Liu, Gaoli Wang, Willi Meier, Santanu Sarkar, Takanori Isobe
ePrint ReportAhmet Ramazan Ağırtaş, Oğuz Yayla
ePrint ReportShingo Sato, Keita Emura, Atsushi Takayasu
ePrint Report07 January 2022
Roberto La Scala, Sergio Polese, Sharwan K. Tiwari, Andrea Visconti
ePrint ReportJiaxin Pan, Benedikt Wagner
ePrint ReportAt the core of our construction are a new abstraction of the existing lossy identification (ID) schemes using dual-mode commitment schemes and a refinement of the framework by Diemert et al. (PKC 2021) which transforms a lossy ID scheme to a signature using sequential OR proofs. In combination, we obtain a tight generic construction of signatures from dual-mode commitments in the multi-user setting. Improving the work of Diemert et al., our new approach can be instantiated using not only the LWE assumption, but also an isogeny-based assumption. We stress that our LWE-based lossy ID scheme in the intermediate step uses a conceptually different idea than the previous lattice-based ones.
Of independent interest, we formally rule out the possibility that the aforementioned ``ID-to-Signature'' methodology can work tightly using parallel OR proofs. In addition to the results of Fischlin et al. (EUROCRYPT 2020), our impossibility result shows a qualitative difference between both forms of OR proofs in terms of tightness.