IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
07 March 2023
University of Amsterdam & QuSoft
Are you fascinated by security? Are you willing to take on the challenge of securing the next generation of computer systems and networks? Do you like to work in a team of young researchers? We are seeking a PhD candidate who is interested in interdisciplinary research on side-channel attacks against quantum devices used in quantum networks.
Quantum technologies are being developed at a fast page. On the one hand, progress on the development of quantum computers poses a serious threat for our security infrastructure, especially for public-key cryptography. On the other hand, quantum components bring novel opportunities since they will be integrated in our networks and could bring novel security functionalities. However, quantum components are mostly experimental, and their security is yet to be studied and assessed in depth. In particular, little is known about their susceptibility against side-channel and physical attacks and, as a direct consequence, we do not know if and which countermeasures can be applied.
This PhD position will study the problem of side channels and physical attacks against quantum devices, understanding the extent to which they could be considered a threat and exploring potential methodologies to counteract and mitigate them. In collaboration with experimental physicists, experiments on real quantum devices are expected to be carried out to assess their robustness.
The fully funded PhD position will be at University of Amsterdam and QuSoft. The position is a part of the Quantum Delta NL Groeifonds project CAT-2, development of a national quantum network and will also involve collaboration with the experimental and theoretical partners of the CAT-2 project.
Closing date for applications:
Contact: Christian Schaffner
More information: https://vacatures.uva.nl/UvA/job/PhD/742058802/
University of Connecticut, CT, USA
The positions provide a great opportunity for students with interest in interdisciplinary projects that combine knowledge from various fields towards the design of secure systems and protocols. We target real-world and timely problems and aim to develop secure and practical solutions backed by rigorous foundations and efficient implementations/thorough performance testing. We are also interested in conceptual projects that contribute in bridging the gap between theory and practice of Cryptography.
For more information about our current and previous projects please check https://ghadaalmashaqbeh.github.io/research/. For interested students, please send your CV to ghada@uconn.edu and provide any relevant information about your research interests, and relevant skills and background.
Closing date for applications:
Contact: Ghada Almashaqbeh
More information: https://ghadaalmashaqbeh.github.io/research/
06 March 2023
Nicky Mouha, Christopher Celi
Bernardo David, Anders Konring, Yuval Ishai, Eyal Kushilevitz, Varun Narayanan
In this work, we tackle the above two challenges simultaneously. We consider a layered MPC model, a simplified variant of the fluid MPC model of Choudhuri et al. (Crypto 2021). Layered MPC is an instance of standard MPC where the interaction pattern is defined by a layered graph of width $n$, allowing each party to send secret messages and broadcast messages only to parties in the next layer. We require perfect security against a malicious adversary who may corrupt at most $t$ parties in each layer. Our main result is a perfect, fully secure layered MPC protocol with an optimal corruption threshold of $t < n/3$, thus extending the BGW feasibility result to the layered setting. This implies perfectly secure MPC protocols against a maximally mobile adversary.
Martin R. Albrecht, Miro Haller, Lenka Mareková, Kenneth G. Paterson
We analyse these new sanity checks and show how they themselves can be exploited to mount novel attacks on MEGA that recover a target user's RSA private key with only slightly higher attack complexity than the original attacks. We identify the presence of an ECB encryption oracle under a target user's master key in the MEGA system; this oracle provides our adversary with the ability to partially overwrite a target user's RSA private key with chosen data, a powerful capability that we use in our attacks. We then present two distinct types of attack, each type exploiting different error conditions arising in the sanity checks and in subsequent cryptographic processing during MEGA's user authentication procedure. The first type appears to be novel and exploits the manner in which the MEGA code handles modular inversion when recomputing $u = q^{-1} \bmod p$. The second can be viewed as a small subgroup attack (van Oorschot and Wiener, EUROCRYPT 1996, Lim and Lee, CRYPTO 1998). We prototype the attacks and show that they work in practice.
As a side contribution, we show how to improve the RSA key recovery attack of Backendal-Haller-Paterson against the unpatched version of MEGA to require only 2 logins instead of the original 512.
We conclude by discussing wider lessons about secure implementation of cryptography that our work surfaces.
Jan Schoone, Joan Daemen
In this paper, we characterize the graph of $\chi$ on periodic sequences. It turns out that $\chi$ is surjective on the set of \emph{all} periodic sequences. We will show what sequences will give collisions after one application of $\chi$. We prove that, for odd $n$, the order of $\chi_n$ (in the group of bijective maps on $\mathbb{F}^n$) is $2^{\lceil \operatorname{lg}(\frac{n+1}2)\rceil}$.
A given periodic sequence lies on a cycle in the graph of $\chi$, or it can be represented as a polynomial. By regarding the divisors of such a polynomial one can see whether it lies in a cycle, or after how many iterations of $\chi$ it will.
Furthermore, we can see, for a given $\sigma$, the length of the cycle in its component in the state diagram. Finally, we extend the surjectivity of $\chi$ to $\mathbb{F}^{\mathbb{Z}}$, thus to include non-periodic sequences.
Yangru Zheng, Juntao Gao, Baocang Wang
Our results show that increasing the length of key seeds is not an effective way anymore to resist the quantum search attacks, and it is necessary to propose new measures to ensure the post-quantum security of symmetric ciphers.
Jean Liénardy, Frédéric Lafitte
Prabhanjan Ananth, Alexander Poremba, Vinod Vaikuntanathan
We define and construct several fundamental cryptographic primitives with key-revocation capabilities, namely pseudorandom functions, secret-key and public-key encryption, and even fully homomorphic encryption, assuming the quantum subexponential hardness of the learning with errors problem. Central to all our constructions is our approach for making the Dual-Regev encryption scheme (Gentry, Peikert and Vaikuntanathan, STOC 2008) revocable.
05 March 2023
Michael Rosenberg
In this work we present LATKE, an iPAKE from lattice assumptions in the random oracle model. In order to achieve security and correctness, we must make changes to CHIP's primitives, security models, and protocol structure.
Lorenzo Grassi, Dmitry Khovratovich, Markus Schofnegger
In this paper, we propose an optimized version of Poseidon, called Poseidon2. The two versions differ in two crucial points. First, Poseidon is a sponge hash function, while Poseidon2 can be either a sponge or a compression function depending on the use case. Secondly, Poseidon2 is instantiated by new and more efficient linear layers with respect to Poseidon. These changes allow to decrease the number of multiplications in the linear layer by up to 90% and the number of constraints in Plonk circuits by up to 70%. This makes Poseidon2 the currently fastest arithmetization-oriented hash function without lookups.
Besides that, we address a recently proposed algebraic attack and propose a simple modification that makes both Poseidon and Poseidon2 secure against this approach.
R Radheshwar, Meenakshi Kansal, Pierrick Méaux, Dibyendu Roy
Cas Cremers, Julian Loss, Benedikt Wagner
To this end, we provide the first holistic security model for Monero's RingCT. In our model, we then prove the security of RingCT. Our framework is modular in that it allows to view RingCT as a combination of various different sub-protocols. This has the benefit that these components can be easily updated in future versions of RingCT with only minor modifications to our analysis. At a technical level, we introduce several new techniques that we believe to be of independent interest. First, we need to make several subtle modifications to the syntax and security properties of existing building blocks (e.g., linkable ring signatures), which result from the unusual way in which they are combined within RingCT. Then, we show how these building blocks can be combined in order to argue security of the top level transaction scheme. As a technical highlight of our proof, we show that our security goals can be mapped to a suitable graph problem. This allows us to take advantage of ideas from the theory of network flows in our analysis.
Fabrice Benhamouda, Mariana Raykova, Karn Seth
Delft, Paesi Bassi, 7 July 2023
Submission deadline: 15 March 2023
Notification: 17 April 2023
TU Wien, Vienna, Austria
We are looking for a candidate with strong scientific foundations and demonstrated expertise in the design of innovative privacy-enhancing technologies that fulfill the needs of our digital society. Desired core areas of competence include but are not limited to:
- Data Privacy
- Privacy in analytics and machine learning
- Theoretical foundations of and formal methods for privacy
- Privacy-preserving protocols, applications, and systems
- Anonymous communication, censorship-resistance
- Cryptographic techniques for privacy
- Human-centered design and usability of privacy technologies
Application deadline: 4 May 2023
For all details and to apply, see: jobs.tuwien.ac.at/Job/203700
Closing date for applications:
Contact: Carmen Keck
More information: https://jobs.tuwien.ac.at/Job/203700
Input Output Global - remote work opportunity
As a Senior Cryptography Engineer in Applied Cryptography at IOG you must be an engineer, an architect, an applied cryptographer and leader - it’s a multifaceted role. You have the exciting challenge of working with bleeding-edge research and technology, always with a focus on the market's needs. You will be a leader to an exceptional team. Working on everything from Post-Quantum prototypes to hand-optimisation of existing primitives to completely new products.
Your mission
- Champion of the applied cryptography team
- Captain end to end development and delivery of new products
- Spearhead prototyping of cryptographic products
- Translate research into rigorous engineering specifications & implementations
- Meticulously review cryptographic protocols and proposed primitives
- Expert knowledge of ZK protocols, including PlonK and IPA commitment scheme
- Expert knowledge of elliptic curve cryptography
- Familiarity with blockchain cryptography and constructions
- Practical experience with implementation of cryptographic primitives
- Expert in terms of secure design (constant time, operational security, management of key material)
- Document code and APIs concisely and unambiguously
- Pragmatically adhere to software engineering principles (modularity, incremental development, no premature optimization, no feature creep, no speculative generality, ...)
- Security sensibility related to cryptographic implementation
- Good theoretical cryptography and mathematical knowledge
- Ability to read cryptographic papers, explain them, and manage delivery of their implementation
Your expertise
Degree in Computer Science/Engineering or Applied Mathematics is desirable but not essential
A minimum of 4-5 years development experience (professional or otherwise) in Rust
Experience working with Git and version control
Expert knowledge of applied cryptographic engineering & best practices
Closing date for applications:
Contact: Marios Nicolaides
Input Output Global - remote work opportunity
As Cryptographic Engineer at IO Global, you will have the exciting challenge of working on cutting-edge research and technology focusing on the market’s needs. You will be working on Midnight, specifically on the zero-knowledge proofs that power Midnight.
The Cryptography Engineering team is growing with the goal of bringing recent academic papers into production. In this team, you will work closely with researchers and engineers, being the bridge between both teams. As Cryptography Engineer you are responsible for writing high-quality code. To support you, our products have software architects, product managers, delivery managers, formal methods specialists, and QA test engineers, with whom you must communicate professionally, effectively, and efficiently.
Your mission
- Working with teams across time zones
- Working independently on software development tasks
- Being proactive and requiring minimal supervision or mentoring to complete tasks
- Reviewing specifications produced by architects and formal methods specialists
- Contributing to the design of algorithms
- Troubleshooting, debugging, and upgrading software
- Writing documentation for the code
- Writing technical user manuals
- Understanding complex cryptographic concepts from academic papers
- Bridging ideas from academic papers to production-ready systems
Requirements
Your expertise
- Excellent Mathematical and Analytical skills.
- Experience with Rust. Not necessarily in industry.
- Knowledge of basic cryptographic concepts (Hash Functions,
- Signature Schemes or Elliptic Curves).
- Degree in computer science or mathematics is desirable, but not essential.
- Experience with systems programming (Rust)
- Skilled in software development methods such as agile programming and test-driven development
- Experience in developing cryptography protocols would be a bonus, as would blockchain experience.
Location IOG is a distributed organization and therefore this is a remote position.
Closing date for applications:
Contact: Marios Nicolaides marios.nicolaides@iohk.io
More information: https://apply.workable.com/io-global/j/4437128D09/
Télécom Paris, Paris, France
Closing date for applications:
Contact: If you want to apply or have more information, please contact Sébastien Canard (sebastien.canard@telecom-paris.fr) or Duong Hieu Phan (hieu.phan@telecom-paris.fr).
Copenhagen, Denmark, 24 August - 25 August 2023
Submission deadline: 15 April 2023
Notification: 15 June 2023