IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
19 March 2024
Nokia Bell Labs; Antwerp, Belgium
At Bell Labs, the research arm of Nokia, we are currently designing and building systems that offer (1) computational integrity, (2) confidentiality, and (3) low-latency operations.
Internship Details:
As an intern in our lab, you'll have the opportunity to contribute to applied research in one of these areas, including:
Zero-Knowledge Proofs: Dive into topics like SNARKs, STARKs, and MPC-in-the-Head to enhance computational integrity. Computing on Encrypted Data: Explore homomorphic encryption (FHE) and secure multiparty computation (MPC) to address confidentiality challenges.
Acceleration: Investigate optimized implementations, software architecture, novel ZKP/FHE/MPC circuits, systems and friendly primitives.
Any other relevant subjects in this area are also welcome, such as zkML, FHE+ML, verifiable FHE, applications of MPC, and beyond.
Candidate Profile:
- You are currently doing a PhD or PostDoc
- Some familiarity with one of the areas: FHE, MPC or ZKP
- Both applied and theoretical researchers are welcome
- Fully funded internship with benefits (based on Belgian income standards)
- Internship any time from now until the end of 2024
- Possibility to visit local university crypto groups (e.g. COSIC KU Leuven)
- A wonderful desk with a view of the Zoo of Antwerp (elephants and bisons visible)
- Having access to the best beers and chocolates in the world
Closing date for applications:
Contact: Emad Heydari Beni (emad.heydari_beni@nokia-bell-labs.com)
Monash University, Melbourne, Australia
At the Department of Software Systems and Cybersecurity (SSC) at Monash, we have several openings for PhD positions. The topics of interest are post-quantum cryptography (based on lattices and/or hash), their applications, and their secure and efficient software and hardware implementations.
- Amongst the benefits:
- We provide highly competitive scholarships opportunities to collaborate with leading academic and industry experts in the above-mentioned areas.
- There will be opportunities to participate in (inter)nationally funded projects.
- We have a highly collaborative and friendly research environment.
- You will have an opportunity to live/study in one of the most liveable and safest cities in the world.
The positions will be filled as soon as suitable candidates are found.
- Entry requirements include:
- Some mathematical and cryptography backgrounds.
- Some knowledge/experience in coding (for example, Python, C/C++, and/or SageMath) is a plus.
- Must have completed (or be about to complete within the next 6 months) a significant research component either as part of their undergraduate (honours) degree or masters degree.
- Should have excellent verbal and written communication skills in English.
How to apply. Please fill out the following form (also clickable from the advertisement title): https://docs.google.com/forms/d/e/1FAIpQLSetFZLvDNug5SzzE-iH97P9TGzFGkZB-ly_EBGOrAYe3zUYBw/viewform?usp=sf_link
Closing date for applications:
Contact: Amin Sakzad (amin.sakzad@monash.edu)
More information: https://www.monash.edu/it/ssc/cybersecurity/people
18 March 2024
Connor Bell, Saba Eskandarian
This paper introduces a new threshold source tracking technique that allows a private messaging platform, with the cooperation of a third-party moderator, to operate a threshold reporting scheme with exact thresholds and no false positives. Unlike prior work, our techniques require no modification of the message delivery process for a standard source tracking scheme, affecting only the abuse reporting procedure, and do not require tuning of probabilistic data structures.
Zhengjun Cao, Zhenfu Cao
Stanislav Kruglik, Son Hoang Dau, Han Mao Kiah, Huaxiong Wang, Liang Feng Zhang
Most existing FSS schemes are based on the existence of one-way functions or pseudo-random generators, and as a result, hiding of function $f$ holds only against computationally bounded adversaries. Protocols employing them as building blocks are computationally secure. Several exceptions mostly focus on DPF for four, eight or $d(t+1)$ servers for positive integer $d$, and none of them provide verifiability.
In this paper, we propose DPF for $d(t+l-1)+1$ servers, where $d$ is a positive integer, offering a better key size compared to the previously proposed DPF for $d(t+1)$ servers and DCF for $dt+1$ servers, also for positive integer $d$. We introduce their verifiable extension in which any set of servers holding $t$ keys cannot persuade us to accept the wrong value of the function. This verifiability notion differs from existing verifiable FSS schemes in the sense that we verify not only the belonging of the function to class $\mathcal{F}$ but also the correctness of computation results. Our schemes provide a secret key size $O(n^{1/d}\cdot s\log(p))$ for DPF and $O(n^{1/d}\cdot s\log(p))$ for DCF, where $p^s$ is the size of group $\mathbb{G}$.
Hans Schmiedel, Runchao Han, Qiang Tang, Ron Steinfeld, Jiangshan Yu
This paper provides theoretical foundations and desired properties for consensus protocols that resist against targeted DoS attacks. In particular, we define the Mobile Crash Adaptive Byzantine (MCAB) model to capture such an attack. In addition, we identify and formalize two properties for consensus protocols under the MCAB model, and analyze their trade-offs. As case studies, we prove that Ouroboros Praos and Algorand are secure in our MCAB model, giving the first formal proofs supporting their security guarantee against targeted DoS attacks, which were previously only informally discussed. We also illustrate an application of our properties to secure a streamlined BFT protocol, chained Hotstuff, against targeted DoS attacks.
Louis Tremblay Thibault, Michael Walter
Ward Beullens, Lucas Dodgson, Sebastian Faller, Julia Hesse
OPRFs are a prime tool for building secure authentication and key exchange from passwords, private set intersection, private information retrieval, and many other privacy-preserving systems. While classical OPRFs run as fast as a TLS Handshake, current *quantum-safe* OPRF candidates are still practically inefficient.
In this paper, we propose a framework for constructing OPRFs from post-quantum multi-party computation. The framework captures a family of so-called "2Hash PRFs", which sandwich a function evaluation in between two hashes. The core of our framework is a compiler that yields an OPRF from a secure evaluation of any function that is key-collision resistant and one-more unpredictable. We instantiate this compiler by providing such functions built from Legendre symbols, and from AES encryption. We then give a case-tailored protocol for securely evaluating our Legendre-based function, built from oblivious transfer (OT) and zero-knowledge proofs (ZKP). Instantiated with lattice-based OT and ZKPs, we obtain a quantum-safe OPRF that completes in 0.57 seconds, with less than 1MB of communication.
Nabil Alkeilani Alkadri, Nico Döttling, Sihang Pu
Manjeet Kaur, Tarun Yadav, Manoj Kumar, Dhananjoy Dey
17 March 2024
CEA-LIST France & University of Paris-Saclay, France
Thus we are looking for a highly motivated PhD candidate with a string background in applied cryptography including FHE/MPC.
The candidate must meet the following requirements
The position is based at the CEA-LIST Nano-Innov campus in Palaiseau, France (30 mins from central Paris), fully funded for three years, no teaching duties, annual leaves, and the usual benefits.
Closing date for applications:
Contact: Olive Chakraborty (olive.chakraborty@cea.fr )
Contact us with your CV and Cover letter for more details on the subject.
15 March 2024
Jamshedpur, India, 20 November - 21 November 2024
Submission deadline: 20 June 2024
Notification: 10 September 2024
UIC 2024: The 21st IEEE International Conference on Ubiquitous Intelligence and Computing (UIC 2024)
Denarau Island, Viti, 2 December - 7 December 2024
Jens Ernstberger, Jan Lauinger, Yinnan Wu, Arthur Gervais, Sebastian Steinhorst
TLS oracles ensure data authenticity beyond the client-server TLS connection, such that clients can obtain data from a server and ensure provenance to any third party, without server-side modifications. Generally, a TLS oracle involves a third party, the verifier, in a TLS session to verify that the data obtained by the client is accurate. Existing protocols for TLS oracles are communication-heavy, as they rely on interactive protocols. We present ORIGO, a TLS oracle with constant communication. Similar to prior work, ORIGO introduces a third party in a TLS session, and provides a protocol to ensure the authenticity of data transmitted in a TLS session, without forfeiting its confidentiality. Compared to prior work, we rely on intricate details specific to TLS 1.3, which allow us to prove correct key derivation, authentication and encryption within a Zero Knowledge Proof (ZKP). This, combined with optimizations for TLS 1.3, leads to an efficient protocol with constant communication in the online phase. Our work reduces online communication by $375 \times$ and online runtime by up to $4.6 \times$, compared to prior work.
Ahmed Bendary, Wendson A. S. Barbosa, Andrew Pomerance, C. Emre Koksal
Aikaterini Mitrokotsa, Sayantan Mukherjee, Mahdi Sedaghat, Daniel Slamanig, Jenit Tomy
Mario Yaksetig
Niklas Nolte, Mohamed Malhou, Emily Wenger, Samuel Stevens, Cathy Yuanchen Li, Francois Charton, Kristin Lauter
Kostas Kryptos Chalkias, Jonas Lindstrøm, Deepak Maram, Ben Riva, Arnab Roy, Alberto Sonnino, Joy Wang
Our approach transcends traditional benchmarking methods by identifying inconsistencies in multi-threaded code, which previously resulted in unfair comparisons. We demonstrate the effectiveness of our methodology in identifying the fastest algorithms for specific cryptographic operations like signing, while revealing hidden performance characteristics and security flaws. The process of continuous benchmarking allowed fastcrypto to break many crypto-operations speed records in the Rust language ecosystem.
A notable discovery in our research is the identification of vulnerabilities and unfair speed claims due to missing padding checks in high-performance Base64 encoding libraries. We also uncover insights into algorithmic implementations such as multi-scalar elliptic curve multiplications, which exhibit different performance gains when applied in different schemes and libraries. This was not evident in conventional benchmarking practices. Further, our analysis highlights bottlenecks in cryptographic algorithms where pre-computed tables can be strategically applied, accounting for L1 and L2 CPU cache limitations.
Our benchmarking framework also reveals that certain algorithmic implementations incur additional overheads due to serialization processes, necessitating a refined `apples to apples' comparison approach. We identified unique performance patterns in some schemes, where efficiency scales with input size, aiding blockchain technologies in optimal parameter selection and data compression.
Crucially, continuous benchmarking serves as a tool for ongoing audit and security assurance. Variations in performance can signal potential security issues during upgrades, such as cleptography, hardware manipulation or supply chain attacks. This was evidenced by critical private key leakage vulnerabilities we found in one of the most popular EdDSA Rust libraries. By providing a dynamic and thorough benchmarking approach, our framework empowers stakeholders to make informed decisions, enhance security measures, and optimize cryptographic operations in an ever-changing digital landscape.