IACR News
Here you can see all recent updates to the IACR webpage. These updates are also available:
25 May 2021
Lei Fan, Jonathan Katz, Phuc Thai, Hong-Sheng Zhou
We are inspired by Bitcoin's ``block-by-block'' design, and we show that a direct and natural mimic of Bitcoin's design via proof-of-stake is secure if the majority 73\% of stake is honest. Our result relies on an interesting upper bound of extending proof-of-stake blockchain we establish: players (who may extend all chains) can generate blockchain at most $2.72\times$ faster than playing the basic strategy of extending the longest chain.
We introduce a novel strategy called ``D-distance-greedy'' strategy, which enables us to construct a class of secure proof-of-stake blockchain protocols, against an \textbf{arbitrary} adversary, even assuming much smaller (than 73\% of) stake is honest. To enable a thorough security analysis in the cryptographic setting, we develop several new techniques: for example, to show the chain growth property, we represent the chain extension process via a Markov chain, and then develop a random walk on the Markov chain; to prove the common prefix property, we introduce a new concept called ``virtual chains'', and then present a reduction from the regular version of common prefix to ``common prefix w.r.t. virtual chains''.
Finally, we note that, ours is the first ``block-by-block'' style of proof-of-stake in the permissionless setting, naturally mimicking Bitcoin's design; it turns out that this feature, again allows us to achieve the ``best possible'' unpredictability property. Other existing provably secure permissionless proof-of-stake solutions are all in an ``epoch-by-epoch'' style, and thus cannot achieve the best possible unpredictability.
21 May 2021
Nishant was born on 22 Feb 1985. He completed his Bachelor's in 2009 from Biju Patnaik University of Technology, Odisha, in Computer Science and Engineering. He next post-graduated from the Centre for Development of Advanced Computing in 2012. He had a brief stint as an Assistant professor from April 2012 to Dec 2014. In the year 2015, he joined Indian Institute of Technology Roorkee for Ph. D., which he completed by the year 2018. During this time he was collaborating with Indian Statistical Institute, Kolkata too. His area of research was Cryptanalysis on Symmetric Ciphers. After the PhD he joined Robert Bosch Engineering and Business Solutions at Bangalore, where he surprised everybody by a remarkable transformation from a Cryptology Researcher to a Security Practitioner. We remember working with Nishant both in Academia and Industry. A link to his publication is at https://dblp.org/pid/07/201-3.html .
Nishant is missed by each of his colleagues. During the cryptology conferences and workshops in India, participants from all over the world were greeted by Nishant with his big and bright smile. That is why we think Nishant should be remembered at the IACR webpage. Our heart reaches out to his family - his mother, sister, wife and little baby daughter. We pray God almighty gives them the strength to overcome these difficult times. In the short span Nishant made his brilliance known to all of us. No doubt he leaves a void that we will never be able to fill. Yet we shall be guided and inspired by him especially his simplicity and ability to handle complicated things. May our friend find peace.
Sugata (IIT Roorkee), Shashwat (Bosch), Subhamoy (ISI Kolkata)
Aalborg University, Department of Mathematical Sciences, Aalborg, Denmark
At the Faculty of Engineering and Science, Department of Mathematical Sciences one or more positions as Assistant Professor in Discrete Mathematics is open for appointment from 1st September 2021 or soon hereafter. The position is available for a period of three years. The Department of Mathematical Sciences houses three education programs, Mathematics, Mathematics-Economics, and Mathematics- Technology. Furthermore, several courses for programs in Engineering and Social Sciences are taught by the Department of Mathematical Sciences. Aalborg University is comprised of three campuses, Aalborg, Esbjerg, and Copenhagen. Teaching responsibilities may include courses at any of the three campuses. For more information about the department, please see: https://www.math.aau.dk/
JOB DESCRIPTIONResearch areas will be within Coding Theory and Cryptography. A selected candidate will have a proven track record of promising research within Coding Theory, Cryptography, or related subjects in Discrete Mathematics.
The ability to contribute to the development of external collaboration and to secure external funding will be taken into account and the applicant is expected to have very good interpersonal skills. Special contributions to the development of educational and teaching related activities will be considered in the overall assessment. The selected candidate is expected to engage in acquiring external funding for research. This will involve collaboration with colleagues from the mathematics department and from other departments at Aalborg University. This includes funding for both theoretical research and for more applied and strategic research activities. Teaching will primarily be in the three mathematical programmes, but also in other study programmes at the university.
Please visit https://www.stillinger.aau.dk to see the full call text and to apply
Closing date for applications:
Contact: You may obtain further professional information from Professor Horia Cornean, phone: +45 9940 8879, e-mail: cornean@math.aau.dk or Head of Department Søren Højsgaard, phone: +45 9940 8801, e-mail: sorenh@math.aau.dk
More information: https://www.stillinger.aau.dk/vis-stilling/?vacancy=1150397
Subspace Labs | Remote (based in SFBA)
Your Responsibilities
- Implement a decoupling of consensus and computation for an EVM style blockchain as described in our technical white paper.
- Develop a system of non-interactive fraud proofs based on an execution trace of incremental commitments to the global state root.
- Develop a VRF-based stake-weighted election mechanism for executors, distinct from the PoR-based space-weighted farmer election.
Basic Requirements
- Experience working with the internals of the EVM, ideally with Geth, Parity/OpenEthereum, or a Substrate based derivative.
- Theoretical background in distributed systems, such as consensus mechanisms, as well as cryptographic fundamentals.
- Strong knowledge of a modern systems programming language, such as Rust, C++, or Go and willing to learn Rust.
Nice to Have
- Familiarity with proof-of-stake consensus, finality gadgets, stateless blockchains, super light clients, and leading blockchain scalability proposals.
- Familiarity with the Rust language and its ecosystem
- Familiarity with Substrate and the Polkadot ecosystem
- A passion for decentralized, peer-to-peer systems and Web3 technologies
Benefits
- A remote work environment with a high degree of autonomy and agency
- You will play a critical role in implementing a new layer one blockchain
- A competitive salary with generous token and equity grants.
Closing date for applications:
Contact: Jeremiah Wagstaff
More information: https://jobs.lever.co/subspacelabs/9d8f9b6d-4141-4782-923a-2872a06c723e?lever-origin=applied&lever-source%5B%5D=IACR
Subspace Labs | Remote (based in SFBA)
Your Responsibilities
- Implement a fault-tolerant, load-balanced, and efficiently-retrievable distributed file-system based on the specifications in our white paper.
- Implement a simplified and streamlined Kademlia Distributed Hash Table (K-DHT) to serve as an indexing layer for the Subspace Network.
- Develop a torrent-style synchronization service for new farmers and a tit-for-tat bandwidth sharing mechanism for existing farmers.
Basic Requirements
- Experience employing or implementing peer-to-peer protocols including gossip networks, distributed hash tables, or distributed file systems.
- Theoretical background in distributed systems, such as peer-to-peer networking, as well as cryptographic fundamentals.
- Strong knowledge of a modern systems programming language, such as Rust, C++, or Go and willing to learn Rust.
Nice to Have
- Familiarity with the LibP2P networking stack.
- Familiarity with the Rust language and its ecosystem
- Familiarity with Substrate and the Polkadot ecosystem
- A passion for decentralized, peer-to-peer systems and Web3 technologies
Benefits
- A remote work environment with a high degree of autonomy and agency
- You will play a critical role in implementing a new layer one blockchain
- A competitive salary with generous token and equity grants.
Closing date for applications:
Contact: Jeremiah Wagstaff
More information: https://jobs.lever.co/subspacelabs/6b2c3833-0bbb-409e-9484-049679390756?lever-origin=applied&lever-source%5B%5D=IACR
Subspace Labs | Remote (based in SFBA)
Your Responsibilities
- Implement a new Nakamoto style consensus algorithm based on a proof-of-useful-storage of the history of the blockchain itself.
- Decouple consensus and computation between two distinct classes of nodes, storage farmers and staked executors, through a system of fraud proofs.
- Implement a series of novel scalability proposals to increase throughput, decrease latency, and achieve fast finality in a permissionless setting.
Basic Requirements
- Experience implementing blockchain consensus protocols, especially Nakamoto style protocols based on proofs of work, stake, or space.
- Theoretical background in distributed systems, consensus algorithms, and cryptographic fundamentals with a focus on Nakamoto style consensus.
- Strong knowledge of a modern systems programming language, such as Rust, C++, or Go and willing to learn Rust.
Nice to Have
- Familiarity with the Rust language and its ecosystem
- Familiarity with Substrate and the Polkadot ecosystem
- Familiarity with proofs of space, storage, replication or space-time.
- A passion for decentralized, peer-to-peer systems and Web3 technologies
Benefits
- A remote work environment with a high degree of autonomy and agency
- You will play a critical role in implementing a new layer one blockchain
- A competitive salary with generous token and equity grants.
Closing date for applications:
Contact: Jeremiah Wagstaff
More information: https://jobs.lever.co/subspacelabs/d5d62ccb-eaaf-43f4-83ad-11ebff2ce3a0?lever-origin=applied&lever-source%5B%5D=IACR
20 May 2021
Mohammed Nabeel, Mohammed Ashraf, Eduardo Chielle, Nektarios G.Tsoutsos, Michail Maniatakos
Prastudy Fauzi, Martha Norberg Hovd, Håvard Raddum
Bhavana Kanukurthi, Sai Lakshmi Bhavana Obbattu, Sruthi Sekar, Jenit Tomy
In this work, we introduce a feature of local reconstructability in NMSS, which allows reconstruction of any portion of a secret by reading just a few locations of the shares. This is a useful feature, especially when the secret is long or when the shares are stored in a distributed manner on a communication network. In this work, we give a compiler that takes in any non-malleable secret sharing scheme and compiles it into a locally reconstructable non-malleable secret sharing scheme. To secret share a message consisting of $k$ blocks of length $l$ each, our scheme would only require reading $l + log k$ bits (in addition to a few more bits, whose quantity is independent of $l$ and $k$) from each party's share (of a reconstruction set) to locally reconstruct a single block of the message.
We show an application of our locally reconstructable non-malleable secret sharing scheme to a computational non-malleable secure message transmission scheme in the pre-processing model, with an improved communication complexity, when transmitting multiple messages.
Lingyue Qin, Xiaoyang Dong, Xiaoyun Wang, Keting Jia, Yunwen Liu
Concretely, we apply this idea to automate the related-key rectangle attacks on SKINNY and ForkSkinny. We propose some new distinguishers with advantage to perform key-recovery attacks. Our key-recovery attacks on a few versions of round-reduced SKINNY and ForkSkinny cover 1 to 2 more rounds than the best previous attacks.
Morten Øygarden, Daniel Smith-Tone, Javier Verbel
Carlo Brunetta, Georgia Tsaloli, Bei Liang, Gustavo Banegas, Aikaterini Mitrokotsa
We implement NIVA and evaluate its communication and execution performance and compare it with the current state-of-the-art, i.e. Segal et al. protocol (CCS 2017) and Xu et al. VerifyNet protocol (IEEE TIFS 2020), resulting in better user's communicated data and
Behzad Abdolmaleki, Hamidreza Khoshakhlagh, Helger Lipmaa
Arsalan Javeed, Cemal Yilmaz, Erkay Savas
Collin Chin, Howard Wu, Raymond Chu, Alessandro Coglio, Eric McCarthy, Eric Smith
We design, implement, and evaluate Leo, a new programming language designed for formally verified, zero-knowledge applications. Leo provisions a powerful execution environment that is not restricted in running time, stack size, or instruction sets. Besides offering application privacy and mitigating miner-extractable value (MEV), Leo achieves two fundamental properties. First, applications are formally verified with respect to their high-level specification. Second, applications can be succinctly verified by anyone, regardless of the size of application.
Leo is the first known programming language to introduce a testing framework, package registry, import resolver, remote compiler, formally defined language, and theorem prover for general-purpose, zero-knowledge applications.