International Association for Cryptologic Research

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16 April 2025

Antonio Guimarães, Hilder V. L. Pereira
ePrint Report ePrint Report
Most homomorphic encryption (FHE) schemes exploit a technique called single-instruction multiple-data (SIMD) to process several messages in parallel. However, they base their security in somehow strong assumptions, such as the hardness of approximate lattice problems with superpolynomial approximation factor. On the other extreme of the spectrum, there are lightweight FHE schemes that have much faster bootstrapping but no SIMD capabilities. On the positive side, the security of these schemes is based on lattice problems with (low-degree) polynomial approximation factor only, which is a much weaker security assumption. Aiming the best of those two options, Micciancio and Sorrell (ICALP'18) proposed a new amortized bootstrapping that can process many messages at once, yielding sublinear time complexity per message, and allowing one to construct FHE based on lattice problems with polynomial approximation factor. Some subsequent works on this line achieve near-optimal asymptotic performance, nevertheless, concrete efficiency remains mostly an open problem. The only existing implementation to date (GPV23, Asiacrypt 2023) requires keys of up to a hundred gigabytes while only providing gains for relatively large messages. In this paper, we introduce a new method for amortized bootstrapping where the number of homomorphic operations required per message is $O(h)$ and the noise overhead is $O(\sqrt{h \lambda} \log \lambda)$, where $h$ is the Hamming weight of the LWE secret key and $\lambda$ is the security parameter. This allows us to use much smaller parameters and to obtain faster running time. Our method is based on a new efficient homomorphic evaluation of sparse polynomial multiplication. We bootstrap 2 to 8-bit messages in 1.1 ms to 26.5 ms, respectively. Compared to TFHE-rs, this represents a performance improvement of 3.9 to 41.5 times while requiring bootstrapping keys up to 50.4 times smaller.
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ilan komargodski, Itamar Schen, Omri Weinstein
ePrint Report ePrint Report
We revisit the longstanding open problem of implementing Nakamoto's proof-of-work (PoW) consensus based on a real-world computational task $T(x)$ (as opposed to artificial random hashing), in a truly permissionless setting where the miner itself chooses the input $x$. The challenge in designing such a Proof-of-Useful-Work (PoUW) protocol, is using the native computation of $T(x)$ to produce a PoW certificate with prescribed hardness and with negligible computational overhead over the worst-case complexity of $T(\cdot)$ -- This ensures malicious miners cannot ``game the system" by fooling the verifier to accept with higher probability compared to honest miners (while using similar computational resources). Indeed, obtaining a PoUW with $O(1)$-factor overhead is trivial for any task $T$, but also useless.

Our main result is a PoUW for the task of Matrix Multiplication $\mathsf{MatMul}(A,B)$ of arbitrary matrices with $1+o(1)$ multiplicative overhead compared to na\"ive $\mathsf{MatMul}$ (even in the presence of Fast Matrix Multiplication-style algorithms, which are currently impractical). We conjecture that our protocol has optimal security in the sense that a malicious prover cannot obtain any significant advantage over an honest prover. This conjecture is based on reducing hardness of our protocol to the task of solving a batch of low-rank random linear equations which is of independent interest.

Since $\mathsf{MatMul}$s are the bottleneck of AI compute as well as countless industry-scale applications, this primitive suggests a concrete design of a new L1 base-layer protocol, which nearly eliminates the energy-waste of Bitcoin mining -- allowing GPU consumers to reduce their AI training and inference costs by ``re-using" it for blockchain consensus, in exchange for block rewards (2-for-1). This blockchain is currently under construction.
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Benjamin Benčina, Benjamin Dowling, Varun Maram, Keita Xagawa
ePrint Report ePrint Report
The Secure Shell (SSH) protocol is one of the first security protocols on the Internet to upgrade itself to resist attacks against future quantum computers, with the default adoption of the "quantum (otherwise, classically)" secure hybrid key exchange in OpenSSH from April 2022. However, there is a lack of a comprehensive security analysis of this quantum-resistant version of SSH in the literature: related works either focus on the hybrid key exchange in isolation and do not consider security of the overall protocol, or analyze the protocol in security models which are not appropriate for SSH, especially in the "post-quantum" setting.

In this paper, we remedy the state of affairs by providing a thorough post-quantum cryptographic analysis of SSH. We follow a "top-down" approach wherein we first prove security of SSH in a more appropriate model, namely, our post-quantum extension of the so-called authenticated and confidential channel establishment (ACCE) protocol security model; our extension which captures "harvest now, decrypt later" attacks could be of independent interest. Then we establish the cryptographic properties of SSH's underlying primitives, as concretely instantiated in practice, based on our protocol-level ACCE security analysis: for example, we prove relevant cryptographic properties of "Streamlined NTRU Prime", a key encapsulation mechanism (KEM) which is used in recent versions of OpenSSH and TinySSH, in the quantum random oracle model, and address open problems related to its analysis in the literature. Notably, our ACCE security analysis of post-quantum SSH relies on the weaker notion of IND-CPA security of the ephemeral KEMs used in the hybrid key exchange. This is in contrast to prior works which rely on the stronger assumption of IND-CCA secure ephemeral KEMs. Hence we conclude the paper with a discussion on potentially replacing IND-CCA secure KEMs in current post-quantum implementations of SSH with simpler and faster IND-CPA secure counterparts, and also provide the corresponding benchmarks.
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Bar Alon, Amos Beimel
ePrint Report ePrint Report
A multi-server private information retrieval (PIR) protocol allows a client to obtain an entry of its choice from a database, held by one or more servers, while hiding the identity of the entry from small enough coalitions of servers. In this paper, we study PIR protocols in which some of the servers are malicious and may not send messages according to the pre-described protocol. In previous papers, such protocols were defined by requiring that they are correct, private, and robust to malicious servers, i.e., by listing 3 properties that they should satisfy. However, 40 years of experience in studying secure multiparty protocols taught us that defining the security of protocols by a list of required properties is problematic.

In this paper, we rectify this situation and define the security of PIR protocols with malicious servers using the real vs. ideal paradigm. We study the relationship between the property-based definition of PIR protocols and the real vs. ideal definition, showing the following results:

- We prove that if we require full security from PIR protocols, e.g., the client outputs the correct value of the database entry with high probability even if a minority of the servers are malicious, then the two definitions are equivalent. This implies that constructions of such protocols that were proven secure using the property-based definition are actually secure under the ``correct'' definition of security.

- We show that if we require security-with-abort from PIR protocols (called PIR protocols with error-detection in previous papers), i.e., protocols in which the user either outputs the correct value or an abort symbol, then there are protocols that are secure under the property-based definition; however, they do not satisfy the real vs. ideal definition, that is, they can be attacked allowing selective abort. This shows that the property-based definition of PIR protocols with security-with-abort is problematic.

- We consider the compiler of Eriguchi et al. (TCC 22) that starts with a PIR protocol that is secure against semi-honest servers and constructs a PIR protocol with security-with-abort; this compiler implies the best-known PIR protocols with security-with-abort. We show that applying this protocol does not result in PIR protocols that are secure according to the real vs. ideal definition. However, we prove that a simple modification of this compiler results in PIR protocols that are secure according to the real vs. ideal definition.
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Nicolas Bon, Céline Chevalier, Guirec Lebrun, Ange Martinelli
ePrint Report ePrint Report
Since the standardization of the Secure Group Messaging protocol Messaging Layer Security (MLS) [4 ], whose core subprotocol is a Continuous Group Key Agreement (CGKA) mechanism named TreeKEM, CGKAs have become the norm for group key exchange protocols. However, in order to alleviate the security issue originating from the fact that all users in a CGKA are able to carry out sensitive operations on the member group, an augmented protocol called Administrated-CGKA (A-CGKA) has been recently created [2].

An A-CGKA includes in the cryptographic protocol the management of the administration rights that restrict the set of privileged users, giving strong security guarantees for the group administration. The protocol designed in [2] is a plugin added to a regular (black-box) CGKA, which consequently add some complexity to the underlying CGKA and curtail its performances. Yet, leaving the fully decentralized paradigm of a CGKA offers the perspective of new protocol designs, potentially more efficient.

We propose in this paper an A-CGKA called SUMAC, which offers strongly enhanced communication and storage performances compared to other A-CGKAs and even to TreeKEM. Our protocol is based on a novel design that modularly combines a regular CGKA used by the administrators of the group and a Tree-structured Multicast Key Agreement (TMKA) [9] – which is a centralized group key exchange mechanism administrated by a single group manager – between each administrator and all the standard users. That TMKA gives SUMAC an asymptotic communication cost logarithmic in the number of users, similarly to a CGKA. However, the concrete performances of our protocol are much better than the latter, especially in the post-quantum framework, due to the intensive use of secret-key cryptography that offers a lighter bandwidth than the public-key encryption schemes from a CGKA.

In practice, SUMAC improves the communication cost of TreeKEM by a factor 1.4 to 2.4 for admin operations and a factor 2 to 38 for user operations. Similarly, its storage cost divides that of TreeKEM by a factor 1.3 to 23 for an administrator and 3.9 to 1,070 for a standard user.

Our analysis of SUMAC is provided along with a ready-to-use open-source rust implementation that confirms the feasibility and the performances of our protocol.
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Qun Liu, Haoyang Wang, Jinliang Wang, Boyun Li, Meiqin Wang
ePrint Report ePrint Report
As one of the famous quantum algorithms, Simon's algorithm enables the efficient derivation of the period of periodic functions in polynomial time. However, the complexity of constructing periodic functions has hindered the widespread application of Simon's algorithm in symmetric-key cryptanalysis. Currently, aside from the exhaustive search-based testing method introduced by Canale et al. at CRYPTO 2022, there is no unified model for effectively searching for periodic distinguishers. Although Xiang et al. established a link between periodic function and truncated differential theory at ToSC 2024, their approach lacks the ability to construct periods using unknown differentials and does not provide automated tools. This limitation underscores the inadequacy of existing methods in identifying periodic distinguishers for complex structures. In this paper, we address the challenge of advancing periodic distinguishers for symmetric-key ciphers. First, we propose a more generalized theory for constructing periodic distinguishers, addressing the limitations of Xiang et al.'s theory in handling unknown differences. We further extend our theory to probabilistic periodic distinguishers, thereby extending the separability property proposed by Hodžić et al. in 2020. As a result, our theory can cover a wider range of periodic distinguishers. Second, we introduce a novel symbolic representation to simplify the search of periodic distinguishers. Based upon this representation, we propose the first fully automated SMT-based search model, which efficiently addresses the challenges of manual searching in complex structures. Finally, we extend the model to SPN structures based on our new theory. Our model has broad applicability through significant advancements in analyzing generalized Feistel structures (GFSs) and SPN-based ciphers. As a general model, we have achieved new quantum distinguishers with the following round configurations: 10 rounds for GFS-4F, 10 rounds for LBlock, 10 rounds for TWINE, and 16 rounds for Skipjack-B, improving the previous best results by 2, 2, 2, and 3 rounds, respectively. In the domain of SPN-based ciphers, our model has enabled the identification of novel periodic distinguishers, including the first 9-round distinguisher for SKINNY and the first 12-round distinguisher for CRAFT. These achievements lay the foundation for quantum cryptanalysis of SPN-based ciphers using Simon’s algorithm.
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Jiayi Kang, Leonard Schild
ePrint Report ePrint Report
Private information retrieval (PIR) allows a client to query a public database privately and serves as a key building block for privacy-enhancing applications. Minimizing query size is particularly important in many use cases, for example when clients operate on low-power or bandwidth-constrained devices. However, existing PIR protocols exhibit large query sizes: to query $2^{25}$ records, the smallest query size of 14.8KB is reported in Respire [Burton et al., CCS'24]. Respire is based on fully homomorphic encryption (FHE), where a common approach to lower the client-to-server communication cost is transciphering. When combining the state-of-the-art transciphering [Bon et al., CHES'24] with Respire, the resulting protocol (referred to as T-Respire) has a 336B query size, while incurring a 16.2x times higher server computation cost than Respire.

Our work presents the Pirouette protocol, which achieves a query size of just 36B without transciphering. This represents a 9.3x reduction compared to T-Respire and a 420x reduction to Respire. For queries over $2^{25}$ records, the single-core server computation in Pirouette is only 2x slower than Respire and 8.1x faster than T-Respire, and the server computation is highly parallelizable. Furthermore, Pirouette requires no database-specific hint for clients and naturally extends to support queries over encrypted databases.
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Rishub Nagpal, Vedad Hadžić, Robert Primas, Stefan Mangard
ePrint Report ePrint Report
Simple power analysis (SPA) attacks and their extensions, profiled and soft-analytical side-channel attacks (SASCA), represent a significant threat to the security of cryptographic devices and remain among the most powerful classes of passive side-channel attacks. In this work, we analyze how numeric representations of secrets can affect the amount of exploitable information leakage available to the adversary. We present an analysis of how mutual information changes as a result of the integer ring size relative to the machine word-size. Furthermore, we study the Redundant Number Representation (RNR) countermeasure and show that its application to ML-KEM can resist the most powerful SASCA attacks and provides a low-cost alternative to shuffling. We eval- uate the performance of RNR-ML-KEM with both simulated and prac- tical SASCA experiments on the ARM Cortex-M4 based on a worst-case attack methodology. We show that RNR-ML-KEM sufficiently renders these attacks ineffective. Finally, we evaluate the performance of the RNR-ML-KEM NTT and INTT and show that SPA security can be achieved with a 62.8% overhead for the NTT and 0% overhead for the INTT relative to the ARM Cortex-M4 reference implementation used.
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Donggeun Kwon, Deukjo Hong, Jaechul Sung, Seokhie Hong
ePrint Report ePrint Report
At ASIACRYPT’19, Bonnetain et al. demonstrated that an S-box can be distinguished from a permutation chosen uniformly at random by quantifying the distances between their behaviors. In this study, we extend this approach by proposing a deep learning-based method to quantify distances between two different S-boxes and evaluate similarities in their design structures. First, we introduce a deep learning-based framework that trains a neural network model to recover the design structure of a given S-box based on its cryptographic table. We then interpret the decision-making process of our trained model to analyze which coefficients in the table play significant roles in identifying S-box structures. Additionally, we investigate the inference results of our model across various scenarios to evaluate its generalization capabilities. Building upon these insights, we propose a novel approach to quantify distances between structurally different S-boxes. Our method effectively assesses structural similarities by embedding S-boxes using the deep learning model and measuring the distances between their embedding vectors. Furthermore, experimental results confirm that this approach is also applicable to structures that the model has never seen during training. Our findings demonstrate that deep learning can reveal the underlying structural similarities between S-boxes, highlighting its potential as a powerful tool for S-box reverse-engineering.
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Nobuyuki Sugio
ePrint Report ePrint Report
Impossible differential attack is one of the major cryptanalytical methods for symmetric-key block ciphers. In this paper, we evaluate the security of SAND-128 against impossible differential attack. SAND is an AND-RX-based lightweight block cipher proposed by Chen et al. in Designs, Codes and Cryptography 2022. There are two variants of SAND, namely SAND-64 and SAND-128, due to structural differences. In this paper, we search for impossible differential distinguishers of SAND-128 using the Constraint Programming (CP) and reveal 14-round impossible differential distinguishers. The number of 14-round distinguishers is $2^{14} \times 7 = 114,688$. Furthermore, we demonstrate a key recovery attack on 21-round SAND-128. The complexities for the attack require $2^{124}$ data, $2^{127.2}$ encryptions, and $2^{122}$ bytes of memory, respectively. Although this result currently achieves the best attack on round-reduced SAND-128, this attack does not threaten the security of SAND-128 against impossible differential attack.
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Daichong Chao, Liehuang Zhu, Dawei Xu, Tong Wu, Chuan Zhang, Fuchun Guo
ePrint Report ePrint Report
This paper compares the relative strengths of prominent security notions for onion encryption within the Tor setting, specifically focusing on CircuitHiding (EUROCRYPT 2018, an anonymity flavor notion) and OnionAE (PETS 2018, a stateful authenticated encryption flavor notion). Although both are state-of-the-art, Tor-specific notions, they have exhibited different definitional choices, along with variations in complexity and usability. By employing an indirect approach, we compare them using a set of onion layer-centric notions: IND\$-CPA, IPR/IPR$^+$, and INT-sfCTXT, to compare with the two, respectively. Since the same notion set that implies OnionAE does not imply CircuitHiding, and vice versa, this leads to the conclusion that OnionAE and CircuitHiding are mutually separable. Therefore, neither notion fully expresses satisfactory security on its own. Importantly, IND\$-CPA, IPR$^+$ (a stronger variant of IPR), and INT-sfCTXT collectively and strictly imply OnionAE and CircuitHiding. Given their onion layer-centric and thus simpler nature, this provides a practical approach to simultaneously satisfying CircuitHiding and OnionAE. Finally, we thoroughly discuss how the results presented in this paper impact the design and evaluation of onion encryption schemes for Tor. While the formal treatment of (general) public-key onion routing has been relatively well-studied, formal treatment tailored to Tor remains insufficient, and thus our work narrows this gap.
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15 April 2025

Antonín Dufka, Semjon Kravtšenko, Peeter Laud, Nikita Snetkov
ePrint Report ePrint Report
In this paper, we present Trilithium: a protocol for distributed key generation and signing compliant with FIPS 204 (ML-DSA). Our protocol allows two parties, "server" and "phone" with assistance of correlated randomness provider (CRP) to produce a standard ML-DSA signature. We prove our protocol to be secure against a malicious server or phone in the universal composability (UC) model, introducing some novel techniques to argue the security of two-party secure computation protocols with active security against one party, but only active privacy against the other. We provide an implementation of our protocol in Rust and benchmark it, showing the practicality of the protocol.
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Kirill Vedenev
ePrint Report ePrint Report
The paper analyzes the security of two recently proposed code-based cryptosystems that employ encryption of the form $y = m G_{\text{pub}} + eE_{pub}$: the Krouk-Kabatiansky-Tavernier (KKT) cryptosystem and the Lau-Ivanov-Ariffin-Chin-Yap (LIACY) cryptosystem. We demonstrate that the KKT cryptosystem can be reduced to a variant of the McEliece scheme, where a small set of columns in the public generator matrix is replaced with random ones. This reduction implies that the KKT cryptosystem is vulnerable to existing attacks on Wieschebrink's encryption scheme, particularly when Generalized Reed-Solomon (GRS) codes are used. In addition, we present a full key-recovery attack on the LIACY cryptosystem by exploiting its linear-algebraic structure and leveraging distinguishers of subcodes of GRS codes. Our findings reveal critical vulnerabilities in both systems, effectively compromising their security despite their novel designs.
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Can Aknesil, Elena Dubrova, Niklas Lindskog, Jakob Sternby, Håkan Englund
ePrint Report ePrint Report
As artificial intelligence plays an increasingly important role in decision-making within critical infrastructure, ensuring the authenticity and integrity of neural networks is crucial. This paper addresses the problem of detecting cloned neural networks. We present a method for identifying clones that employs a combination of metrics from both the information and physical domains: output predictions, probability score vectors, and power traces measured from the device running the neural network during inference. We compare the effectiveness of each metric individually, as well as in combination. Our results show that the effectiveness of both the information and the physical domain metrics is excellent for a clone that is a near replica of the target neural network. Furthermore, both the physical domain metric individually and the hybrid approach outperformed the information domain metrics at detecting clones whose weights were extracted with low accuracy. The presented method offers a practical solution for verifying neural network authenticity and integrity. It is particularly useful in scenarios where neural networks are at risk of model extraction attacks, such as in cloud-based machine learning services.
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Giacomo Pope, Krijn Reijnders, Damien Robert, Alessandro Sferlazza, Benjamin Smith
ePrint Report ePrint Report
We show that Montgomery ladders compute pairings as a by-product, and explain how a small adjustment to the ladder results in simple and efficient algorithms for the Weil and Tate pairing on elliptic curves using cubical arithmetic. We demonstrate the efficiency of the resulting cubical pairings in several applications from isogeny-based cryptography. Cubical pairings are simpler and more performant than pairings computed using Miller's algorithm: we get a speed-up of over 40% for use-cases in SQIsign, and a speed-up of about 7% for use-cases in CSIDH. While these results arise from a deep connection to biextensions and cubical arithmetic, in this article we keep things as concrete (and digestible) as possible. We provide a concise and complete introduction to cubical arithmetic as an appendix.
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Shimin Pan, Tsz Hon Yuen, Siu-Ming Yiu
ePrint Report ePrint Report
Multisignature schemes are crucial for secure operations in digital wallets and escrow services within smart contract platforms, particularly in the emerging post-quantum era. Existing post-quantum multisignature constructions either do not address the stringent requirements of the Quantum Random Oracle Model (QROM) or fail to achieve practical efficiency due to suboptimal parameter choices.

In this paper, we present a novel Dilithium-based multisignature scheme designed to be secure in the QROM and optimized for practical use. Our scheme operates over the polynomial ring $\mathbb{Z}_q[X]/(x^n+1)$ with $q \equiv 1 \pmod{2n}$, enabling full splitting of the ring and allowing for efficient polynomial arithmetic via the Number Theoretic Transform (NTT). This structure not only ensures post-quantum security but also bridges the gap between theoretical constructs and real-world implementation needs.

We further propose a new hardness assumption, termed $\nu$-SelfTargetMSIS, extending SelfTargetMSIS (Eurocrypt 2018) to accommodate multiple challenge targets. We prove its security in the QROM and leverage it to construct a secure and efficient multisignature scheme. Our approach avoids the limitations of previous techniques, reduces security loss in the reduction, and results in a more compact and practical scheme suitable for deployment in post-quantum cryptographic systems.
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Jianming Lin, Damien Robert, Chang-An Zhao, Yuhao Zheng
ePrint Report ePrint Report
Bilinear pairings constitute a cornerstone of public-key cryptography, where advancements in Tate pairings and their efficient variants have emerged as a critical research domain within cryptographic science. Currently, the computation of pairings can be effectively implemented through three distinct algorithmic approaches: Miller’s algorithm, the elliptic net algorithm (as developed by Stange), and cubical-based algorithms (as proposed by Damien Robert). Biextensions are the geometric object underlying the arithmetic of pairings, and all three approaches can be seen as a different way to represent biextension elements. In this paper, we revisit the biextension geometric point of view for pairing computation and investigate in more detail the cubical representation for pairing-based cryptography. Utilizing the twisting isomorphism, we derive explicit formulas and algorithmic frameworks for the ate pairing and optimal ate pairing computations. Additionally, we present detailed formulas and introduce an optimized shared cubical ladder algorithm for super-optimal ate pairings. Through concrete computational analyses, we compare the performance of our cubical-based methods with the Miller's algorithm on various well-known families of pairing-friendly elliptic curves. Our results demonstrate that the cubical-based algorithm outperforms the Miller's algorithm by bits in certain specific situations, establishing its potential as an alternative for pairing computation.
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Chao Niu, Benqiang Wei, Zhicong Huang, Zhaomin Yang, Cheng Hong, Meiqin Wang, Tao Wei
ePrint Report ePrint Report
Fully Homomorphic Encryption (FHE) enables computation on encrypted data without decryption, demonstrating significant potential for privacy-preserving applications. However, FHE faces several challenges, one of which is the significant plaintext-to-ciphertext expansion ratio, resulting in high communication overhead between client and server. The transciphering technique can effectively address this problem by first encrypting data with a space-efficient symmetric cipher, then converting symmetric ciphertext to FHE ciphertext without decryption.

Numerous FHE-friendly symmetric ciphers and transciphering methods have been developed by researchers, each with unique advantages and limitations. These often require extensive knowledge of both symmetric cryptography and FHE to fully grasp, making comparison and selection among these schemes challenging. To address this, we conduct a comprehensive survey of over 20 FHE-friendly symmetric ciphers and transciphering methods, evaluating them based on criteria such as security level, efficiency, and compatibility. We have designed and executed experiments to benchmark the performance of the feasible combinations of symmetric ciphers and transciphering methods across various application scenarios. Our findings offer insights into achieving efficient transciphering tailored to different task contexts. Additionally, we make our example code available open-source, leveraging state-of-the-art FHE implementations.
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Yongcheng Song, Rongmao Chen, Fangguo Zhang, Xinyi Huang, Jian Weng, Huaxiong Wang
ePrint Report ePrint Report
In this paper, we investigate the Extended Gabidulin (EG) codes and the Interleaved EG (IEG) codes, and enhance the Rank Quasi-Cyclic (RQC) encryption scheme. Our primary contribution is the development of a general decoding algorithm for (I)EG codes, for which we precisely provide the DFR, bound the decoding capacity, and estimate the decoding complexity. As the core tool, we demonstrate that the Linear Reconstruction (LR) problem derived from the decoding (I)EG codes problem can be probabilistically solved, enabling (I)EG codes to achieve arbitrarily small DFRs, decode up to the rank Gilbert-Varshamov bound (even close to the minimal distance), and decode by the Welch-Berlekamp like algorithm. An interesting and important byproduct is that we demonstrate that decoding interleaved Gabidulin codes can be achieved deterministically by solving the LR problem. We finally apply the EG codes to improve RQC (NIST PQC & Asiacrypt 2023). For 128-bit security, our optimized RQC reduces bandwidth by 69 % and 34 % compared to the original versions, respectively. The scheme also achieves at least 50% improvement in efficiency and mitigates MM algebraic attacks (as discussed in Eurocrypt 2020, Asiacrypt 2020 & 2023) as EG codes facilitate schemes operating over smaller finite fields. Overall, our scheme outperforms code-based schemes of NIST PQC Round 4 submissions, such as HQC, BIKE, and Classic McEliece, in terms of bandwidth. A conservative parameters set still remains competitive bandwidths.
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China Telecom Overseas Talent Recruitment Program
Job Posting Job Posting

Job Description: 1) Lead or participate in technical research and applications for data privacy, data security, cryptography and data circulation system, including performance upgrades for the multi-privacy-preserving computing platform, software-hardware integration architecture design, trusted data circulation infrastructure development and real-world industrial applications. 2) Drive R&D of privacy-preserving technologies for LLM in distributed scenarios, including cross-domain secure training/fine-tuning/inference methods, and promote industry-leading security solutions. 3) Participate in planning and capability building for data element infrastructure, aligning with strategies to formulate technical roadmap and implement projects. 4) The positions are available immediately until filled, and the working location can be Beijing or Shanghai.

Basic Requirements: 1. Specialization: Cryptography, data security and privacy, artificial intelligence, cybersecurity, computer software development, etc. 2. Age: Under 35 years old. 3. Education: Ph.D. or Post Doc. 4. Experience: 3 years of overseas work experience (negotiable) with globally renowned employers.

Technical Requirements: 1. Expertise in cryptography, federated learning, LLM and data security/privacy, or software-hardware integration. Candidates must meet at least one of: a) Proficiency in deep learning/ML/NLP fundamentals, with experience in LLMs, distributed training security, frameworks (TensorFlow/PyTorch). b) In-depth understanding of applied cryptography, including but are not limited to the following sub-areas: secure multi-party computation, lattice-based cryptography, cryptography and its application in AI. 2. PhD or postdoctoral experience from renowned institutions or enterprises. Familiarity with applied cryptography domains (MPC, lattice-based cryptography, post-quantum crypto, homomorphic encryption, etc.), with ≥3 publications in top journals/conferences.

Closing date for applications:

Contact: Dr. He, 17316480416@189.cn

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