This paper reviews, from bottom to top, a polynomial-time algorithm to correct t errors in classical binary Goppa codes defined by squarefree degree- t polynomials. The proof is factored through a proof of a simple Reed–Solomon decoder, and the algorithm is simpler than Patterson's algorithm. All algorithm layers are expressed as Sage scripts backed by test scripts. All theorems are formally verified. The paper also covers the use of decoding inside the Classic McEliece cryptosystem, including reliable recognition of valid inputs.
本文自下而上评述了一种多项式时间算法，用于纠正由无平方 t 度多项式定义的经典二进制 Goppa 码中的 t 错误。证明是通过一个简单的里德-所罗门解码器的证明来实现的，该算法比帕特森算法更简单。所有算法层都以 Sage 脚本表达，并有测试脚本支持。所有定理都经过正式验证。论文还涉及经典 McEliece 密码系统内部解码的使用，包括有效输入的可靠识别。
{"title":"Understanding binary-Goppa decoding","authors":"D. Bernstein","doi":"10.62056/angy4fe-3","DOIUrl":"https://doi.org/10.62056/angy4fe-3","url":null,"abstract":"This paper reviews, from bottom to top, a polynomial-time algorithm to correct \u0000 \u0000 t\u0000 \u0000 errors in classical binary Goppa codes defined by squarefree degree-\u0000 \u0000 t\u0000 \u0000 polynomials. The proof is factored through a proof of a simple Reed–Solomon decoder, and the algorithm is simpler than Patterson's algorithm. All algorithm layers are expressed as Sage scripts backed by test scripts. All theorems are formally verified. The paper also covers the use of decoding inside the Classic McEliece cryptosystem, including reliable recognition of valid inputs.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"21 1","pages":"473"},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140721950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Atapoor, Karim Baghery, Hilder V. L. Pereira, Jannik Spiessens
Fully Homomorphic Encryption (FHE) is a prevalent cryptographic primitive that allows for computation on encrypted data. In various cryptographic protocols, this enables outsourcing computation to a third party while retaining the privacy of the inputs to the computation. However, these schemes make an honest-but-curious assumption about the adversary. Previous work has tried to remove this assumption by combining FHE with Verifiable Computation (VC). Recent work has increased the flexibility of this approach by introducing integrity checks for homomorphic computations over rings. However, efficient FHE for circuits of large multiplicative depth also requires non-ring computations called maintenance operations, i.e. modswitching and keyswitching, which cannot be efficiently verified by existing constructions. We propose the first efficiently verifiable FHE scheme that allows for arbitrary depth homomorphic circuits by utilizing the double-CRT representation in which FHE schemes are typically computed, and using lattice-based SNARKs to prove components of this computation separately, including the maintenance operations. Therefore, our construction can theoretically handle bootstrapping operations. We also present the first implementation of a verifiable computation on encrypted data for a computation that contains multiple ciphertext-ciphertext multiplications. Concretely, we verify the homomorphic computation of an approximate neural network containing three layers and >100 ciphertexts in less than 1 second while maintaining reasonable prover costs.
{"title":"Verifiable FHE via Lattice-based SNARKs","authors":"S. Atapoor, Karim Baghery, Hilder V. L. Pereira, Jannik Spiessens","doi":"10.62056/a6ksdkp10","DOIUrl":"https://doi.org/10.62056/a6ksdkp10","url":null,"abstract":"Fully Homomorphic Encryption (FHE) is a prevalent cryptographic primitive that allows for computation on encrypted data. In various cryptographic protocols, this enables outsourcing computation to a third party while retaining the privacy of the inputs to the computation. However, these schemes make an honest-but-curious assumption about the adversary. Previous work has tried to remove this assumption by combining FHE with Verifiable Computation (VC). Recent work has increased the flexibility of this approach by introducing integrity checks for homomorphic computations over rings. However, efficient FHE for circuits of large multiplicative depth also requires non-ring computations called maintenance operations, i.e. modswitching and keyswitching, which cannot be efficiently verified by existing constructions. We propose the first efficiently verifiable FHE scheme that allows for arbitrary depth homomorphic circuits by utilizing the double-CRT representation in which FHE schemes are typically computed, and using lattice-based SNARKs to prove components of this computation separately, including the maintenance operations. Therefore, our construction can theoretically handle bootstrapping operations. We also present the first implementation of a verifiable computation on encrypted data for a computation that contains multiple ciphertext-ciphertext multiplications. Concretely, we verify the homomorphic computation of an approximate neural network containing three layers and >100 ciphertexts in less than 1 second while maintaining reasonable prover costs.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"28 1","pages":"32"},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140723304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The size of the authentication tag represents a significant overhead for applications that are limited by bandwidth or memory. Hence, some authenticated encryption designs have a smaller tag than the required privacy level, which was also suggested by the NIST lightweight cryptography standardization project. In the ToSC 2022, two papers have raised questions about the IND-CCA security of AEAD schemes in this situation. These papers show that (a) online AE cannot provide IND-CCA security beyond the tag length, and (b) it is possible to have IND-CCA security beyond the tag length in a restricted Encode-then-Encipher framework. In this paper, we address some of the remaining gaps in this area. Our main result is to show that, for a fixed stretch, Pseudo-Random Injection security implies IND-CCA security as long as the minimum ciphertext size is at least as large as the required IND-CCA security level. We also show that this bound is tight and that any AEAD scheme that allows empty plaintexts with a fixed stretch cannot achieve IND-CCA security beyond the tag length. Next, we look at the weaker notion of MRAE security, and show that two-pass schemes that achieve MRAE security do not achieve IND-CCA security beyond the tag size. This includes SIV and rugged PRPs.
{"title":"CCA Security with Short AEAD Tags","authors":"Mustafa Khairallah","doi":"10.62056/aevua69p1","DOIUrl":"https://doi.org/10.62056/aevua69p1","url":null,"abstract":"The size of the authentication tag represents a significant overhead for applications that are limited by bandwidth or memory. Hence, some authenticated encryption designs have a smaller tag than the required privacy level, which was also suggested by the NIST lightweight cryptography standardization project. In the ToSC 2022, two papers have raised questions about the IND-CCA security of AEAD schemes in this situation. These papers show that (a) online AE cannot provide IND-CCA security beyond the tag length, and (b) it is possible to have IND-CCA security beyond the tag length in a restricted Encode-then-Encipher framework. In this paper, we address some of the remaining gaps in this area. Our main result is to show that, for a fixed stretch, Pseudo-Random Injection security implies IND-CCA security as long as the minimum ciphertext size is at least as large as the required IND-CCA security level. We also show that this bound is tight and that any AEAD scheme that allows empty plaintexts with a fixed stretch cannot achieve IND-CCA security beyond the tag length. Next, we look at the weaker notion of MRAE security, and show that two-pass schemes that achieve MRAE security do not achieve IND-CCA security beyond the tag size. This includes SIV and rugged PRPs.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"53 1","pages":"23"},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140725115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In a multiparty signing protocol, also known as a threshold signature scheme, the private signing key is shared amongst a set of parties and only a quorum of those parties can generate a signature. Research on multiparty signing has been growing in popularity recently due to its application to cryptocurrencies. Most work has focused on reducing the number of rounds to two, and as a result: (a) are not fully simulatable in the sense of MPC real/ideal security definitions, and/or (b) are not secure under concurrent composition, and/or (c) utilize non-standard assumptions of different types in their proofs of security. In this paper, we describe a simple three-round multiparty protocol for Schnorr signatures that is secure for any number of corrupted parties; i.e., in the setting of a dishonest majority. The protocol is fully simulatable, secure under concurrent composition, and proven secure in the standard model or random-oracle model (depending on the instantiations of the commitment and zero-knowledge primitives). The protocol realizes an ideal Schnorr signing functionality with perfect security in the ideal commitment and zero-knowledge hybrid model (and thus the only assumptions needed are for realizing these functionalities). In our presentation, we do not assume that all parties begin with the message to be signed, the identities of the participating parties and a unique common session identifier, since this is often not the case in practice. Rather, the parties achieve consensus on these parameters as the protocol progresses.
{"title":"Simple Three-Round Multiparty Schnorr Signing with Full Simulatability","authors":"Yehuda Lindell","doi":"10.62056/a36c0l5vt","DOIUrl":"https://doi.org/10.62056/a36c0l5vt","url":null,"abstract":"In a multiparty signing protocol, also known as a threshold signature scheme, the private signing key is shared amongst a set of parties and only a quorum of those parties can generate a signature. Research on multiparty signing has been growing in popularity recently due to its application to cryptocurrencies. Most work has focused on reducing the number of rounds to two, and as a result: (a) are not fully simulatable in the sense of MPC real/ideal security definitions, and/or (b) are not secure under concurrent composition, and/or (c) utilize non-standard assumptions of different types in their proofs of security. In this paper, we describe a simple three-round multiparty protocol for Schnorr signatures that is secure for any number of corrupted parties; i.e., in the setting of a dishonest majority. The protocol is fully simulatable, secure under concurrent composition, and proven secure in the standard model or random-oracle model (depending on the instantiations of the commitment and zero-knowledge primitives). The protocol realizes an ideal Schnorr signing functionality with perfect security in the ideal commitment and zero-knowledge hybrid model (and thus the only assumptions needed are for realizing these functionalities).\u0000 In our presentation, we do not assume that all parties begin with the message to be signed, the identities of the participating parties and a unique common session identifier, since this is often not the case in practice. Rather, the parties achieve consensus on these parameters as the protocol progresses.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"13 6","pages":"374"},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140726955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.56553/popets-2024-0041
Ni Trieu, Avishay Yanai, Jiahui Gao
We describe a new paradigm for multi-party private set intersection cardinality (PSI-CA) that allows $n$ parties to compute the intersection size of their datasets without revealing any additional information. We explore a variety of instantiations of this paradigm. By operating under the assumption that a particular subset of parties refrains from collusion, our protocols avoid computationally expensive public-key operations and are secure in the presence of a semi-honest adversary. We demonstrate the practicality of our PSI-CA with an implementation. For $n=16$ parties with data-sets of $2^{20}$ items each, our server-aided variant takes 71 seconds. Interestingly, in the server-less setting, the same task takes only 7 seconds. To the best of our knowledge, this is the first `special purpose' implementation of a multi-party PSI-CA from symmetric-key techniques (i.e. an implementation that does not rely on a generic underlying MPC).We study two interesting applications -- heatmap computation and associated rule learning (ARL) -- that can be computed securely using a dot-product as a building block. We analyse the performance of securely computing heatmap and ARL using our protocol and compare that to the state-of-the-art.
{"title":"Multiparty Private Set Intersection Cardinality and Its Applications","authors":"Ni Trieu, Avishay Yanai, Jiahui Gao","doi":"10.56553/popets-2024-0041","DOIUrl":"https://doi.org/10.56553/popets-2024-0041","url":null,"abstract":"We describe a new paradigm for multi-party private set intersection cardinality (PSI-CA) that allows $n$ parties to compute the intersection size of their datasets without revealing any additional information. We explore a variety of instantiations of this paradigm. By operating under the assumption that a particular subset of parties refrains from collusion, our protocols avoid computationally expensive public-key operations and are secure in the presence of a semi-honest adversary. We demonstrate the practicality of our PSI-CA with an implementation. For $n=16$ parties with data-sets of $2^{20}$ items each, our server-aided variant takes 71 seconds. Interestingly, in the server-less setting, the same task takes only 7 seconds. To the best of our knowledge, this is the first `special purpose' implementation of a multi-party PSI-CA from symmetric-key techniques (i.e. an implementation that does not rely on a generic underlying MPC).We study two interesting applications -- heatmap computation and associated rule learning (ARL) -- that can be computed securely using a dot-product as a building block. We analyse the performance of securely computing heatmap and ARL using our protocol and compare that to the state-of-the-art.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"268 2","pages":"735"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140780417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.56553/popets-2024-0054
Arthur Américo, Allison Bishop, Paul Cesaretti, Garrison Grogan, Adam McKoy, Robert Moss, Lisa Oakley, Marcel Ribeiro, Mohammad Shokri
We present a new framework for defining information leakage in the setting of US equities trading, and construct methods for deriving trading schedules that stay within specified information leakage bounds. Our approach treats the stock market as an interactive protocol performed in the presence of an adversary, and draws inspiration from the related disciplines of differential privacy as well as quantitative information flow. We apply a linear programming solver using examples from historical trade and quote (TAQ) data for US equities and describe how this framework can inform actual algorithmic trading strategies.
{"title":"Defining and Controlling Information Leakage in US Equities Trading","authors":"Arthur Américo, Allison Bishop, Paul Cesaretti, Garrison Grogan, Adam McKoy, Robert Moss, Lisa Oakley, Marcel Ribeiro, Mohammad Shokri","doi":"10.56553/popets-2024-0054","DOIUrl":"https://doi.org/10.56553/popets-2024-0054","url":null,"abstract":"We present a new framework for defining information leakage in the setting of US equities trading, and construct methods for deriving trading schedules that stay within specified information leakage bounds. Our approach treats the stock market as an interactive protocol performed in the presence of an adversary, and draws inspiration from the related disciplines of differential privacy as well as quantitative information flow. We apply a linear programming solver using examples from historical trade and quote (TAQ) data for US equities and describe how this framework can inform actual algorithmic trading strategies.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"285 ","pages":"971"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140769402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.56553/popets-2024-0056
Faxing Wang, Shaanan N. Cohney, R. Wahby, Joseph Bonneau
Modern secure messaging protocols typically aim to provide deniability. Achieving this requires that convincing cryptographic transcripts can be forged without the involvement of genuine users. In this work, we observe that parties may wish to revoke deniability and avow a conversation after it has taken place. We propose a new protocol called Not-on-the-Record-Yet (NOTRY) which enables users to prove a prior conversation transcript is genuine. As a key building block we propose avowable designated verifier proofs which may be of independent interest. Our implementation in- curs roughly 8× communication and computation overhead over the standard Signal protocol during regular operation. We find it is nonetheless deployable in a realistic setting as key exchanges (the source of the overhead) still complete in just over 1ms on a modern computer. The avowal protocol induces only constant computation and communication performance for the communicating parties and scales linearly in the number of messages avowed for the verifier—in the tens of milliseconds per avowal.
现代安全信息传输协议通常旨在提供可抵赖性。要做到这一点，需要在没有真正用户参与的情况下伪造出令人信服的加密记录。在这项工作中，我们注意到，各方可能希望在对话发生后撤销不可否认性并公开对话内容。我们提出了一种名为 "尚未记录"（Not-on-the-Record-Yet，NOTRY）的新协议，它能让用户证明之前的对话记录是真实的。作为一个关键的构件，我们提出了可公开的指定验证者证明，这可能会引起人们的兴趣。在正常运行时，我们的实现比标准 Signal 协议的通信和计算开销高出约 8 倍。但我们发现，在现实环境中，它还是可以部署的，因为在现代计算机上，密钥交换（开销的来源）仍然只需 1 毫秒多一点就能完成。对于通信双方来说，验证协议只产生恒定的计算和通信性能，并且与验证者验证的信息数量成线性关系--每次验证只需几十毫秒。
{"title":"NOTRY: deniable messaging with retroactive avowal","authors":"Faxing Wang, Shaanan N. Cohney, R. Wahby, Joseph Bonneau","doi":"10.56553/popets-2024-0056","DOIUrl":"https://doi.org/10.56553/popets-2024-0056","url":null,"abstract":"Modern secure messaging protocols typically aim to provide deniability. Achieving this requires that convincing cryptographic transcripts can be forged without the involvement of genuine users. In this work, we observe that parties may wish to revoke deniability and avow a conversation after it has taken place. We propose a new protocol called Not-on-the-Record-Yet (NOTRY) which enables users to prove a prior conversation transcript is genuine. As a key building block we propose avowable designated verifier proofs which may be of independent interest. Our implementation in- curs roughly 8× communication and computation overhead over the standard Signal protocol during regular operation. We find it is nonetheless deployable in a realistic setting as key exchanges (the source of the overhead) still complete in just over 1ms on a modern computer. The avowal protocol induces only constant computation and communication performance for the communicating parties and scales linearly in the number of messages avowed for the verifier—in the tens of milliseconds per avowal.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"32 ","pages":"1926"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140770874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.56553/popets-2024-0040
Dimitris Mouris, Daniel Masny, Ni Trieu, Shubho Sengupta, Prasad Buddhavarapu, Benjamin M. Case
Private matching for compute (PMC) establishes a match between two datasets owned by mutually distrusted parties (C and P) and allows the parties to input more data for the matched records for arbitrary downstream secure computation without rerunning the private matching component. The state-of-the-art PMC protocols only support two parties and assume that both parties can participate in computationally intensive secure computation. We observe that such operational overhead limits the adoption of these protocols to solely powerful entities as small data owners or devices with minimal computing power will not be able to participate. We introduce two protocols to delegate PMC from party P to untrusted cloud servers, called delegates, allowing multiple smaller P parties to provide inputs containing identifiers and associated values. Our Delegated Private Matching for Compute protocols, called DPMC and DsPMC, establish a join between the datasets of party C and multiple delegators P based on multiple identifiers and compute secret shares of associated values for the identifiers that the parties have in common. We introduce a rerandomizable encrypted oblivious pseudorandom function (OPRF) primitive, called EO, which allows two parties to encrypt, mask, and shuffle their data. Note that EO may be of independent interest. Our DsPMC protocol limits the leakages of DPMC by combining our EO scheme and secure three-party shuffling. Finally, our implementation demonstrates the efficiency of our constructions by outperforming related works by approximately 10x for the total protocol execution and by at least 20x for the computation on the delegators.
计算专用匹配（PMC）在互不信任的双方（C 和 P）拥有的两个数据集之间建立匹配，并允许双方为匹配记录输入更多数据，以进行任意下游安全计算，而无需重新运行专用匹配组件。最先进的 PMC 协议仅支持两方，并假设双方都能参与计算密集型安全计算。我们注意到，这种操作开销限制了这些协议的采用，因为计算能力极低的小型数据所有者或设备将无法参与，因此只有强大的实体才能采用这些协议。我们介绍了两种将 PMC 从 P 方委托给不受信任的云服务器（称为委托方）的协议，允许多个较小的 P 方提供包含标识符和相关值的输入。我们的计算委托私有匹配协议（称为 DPMC 和 DsPMC）基于多个标识符在 C 方和多个委托方 P 的数据集之间建立连接，并计算各方共同标识符的关联值的秘密份额。我们引入了一种可重新随机化的加密遗忘伪随机函数（OPRF）原型，称为 EO，它允许双方对数据进行加密、屏蔽和洗牌。请注意，EO 可能具有独立的意义。我们的 DsPMC 协议结合了 EO 方案和安全的三方洗牌，从而限制了 DPMC 的泄漏。最后，我们的实现证明了我们构建的效率，在整个协议执行过程中，我们的性能大约是相关研究的 10 倍，而在委托人的计算方面，我们的性能至少是相关研究的 20 倍。
{"title":"Delegated Private Matching for Compute","authors":"Dimitris Mouris, Daniel Masny, Ni Trieu, Shubho Sengupta, Prasad Buddhavarapu, Benjamin M. Case","doi":"10.56553/popets-2024-0040","DOIUrl":"https://doi.org/10.56553/popets-2024-0040","url":null,"abstract":"Private matching for compute (PMC) establishes a match between two datasets owned by mutually distrusted parties (C and P) and allows the parties to input more data for the matched records for arbitrary downstream secure computation without rerunning the private matching component. The state-of-the-art PMC protocols only support two parties and assume that both parties can participate in computationally intensive secure computation. We observe that such operational overhead limits the adoption of these protocols to solely powerful entities as small data owners or devices with minimal computing power will not be able to participate.\u0000 We introduce two protocols to delegate PMC from party P to untrusted cloud servers, called delegates, allowing multiple smaller P parties to provide inputs containing identifiers and associated values. Our Delegated Private Matching for Compute protocols, called DPMC and DsPMC, establish a join between the datasets of party C and multiple delegators P based on multiple identifiers and compute secret shares of associated values for the identifiers that the parties have in common. We introduce a rerandomizable encrypted oblivious pseudorandom function (OPRF) primitive, called EO, which allows two parties to encrypt, mask, and shuffle their data. Note that EO may be of independent interest. Our DsPMC protocol limits the leakages of DPMC by combining our EO scheme and secure three-party shuffling. Finally, our implementation demonstrates the efficiency of our constructions by outperforming related works by approximately 10x for the total protocol execution and by at least 20x for the computation on the delegators.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"78 ","pages":"12"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140770281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-01DOI: 10.56553/popets-2024-0038
Sebastian Hasler, Pascal Reisert, Marc Rivinius, Ralf Küsters
In recent years, actively secure SPDZ-like protocols for dishonest majority, like SPDZ2k, Overdrive2k, and MHz2k, over base rings Z2k have become more and more efficient. In this paper, we present a new actively secure MPC protocol Multipars that outperforms these state-of-the-art protocols over Z2k by more than a factor of 2 in the two-party setup in terms of communication. Multipars is the first actively secure N-party protocol over Z2k that is based on linear homomorphic encryption (LHE) in the offline phase (instead of oblivious transfer or somewhat homomorphic encryption in previous works). The strong performance of Multipars relies on a new adaptive packing for BGV ciphertexts that allows us to reduce the parameter size of the encryption scheme and the overall communication cost. Additionally, we use modulus switching for further size reduction, a new type of enhanced CPA security over Z2k, a truncation protocol for Beaver triples, and a new LHE-based offline protocol without sacrificing over Z2k. We have implemented Multipars and therewith provide the fastest preprocessing phase over Z2k. Our evaluation shows that Multipars offers at least a factor of 8 lower communication costs and up to a factor of 15 faster runtime in the WAN setting compared to the currently best available actively secure MPC implementation over Z2k.
{"title":"Multipars: Reduced-Communication MPC over Z2k","authors":"Sebastian Hasler, Pascal Reisert, Marc Rivinius, Ralf Küsters","doi":"10.56553/popets-2024-0038","DOIUrl":"https://doi.org/10.56553/popets-2024-0038","url":null,"abstract":"In recent years, actively secure SPDZ-like protocols for dishonest majority, like SPDZ2k, Overdrive2k, and MHz2k, over base rings Z2k have become more and more efficient. In this paper, we present a new actively secure MPC protocol Multipars that outperforms these state-of-the-art protocols over Z2k by more than a factor of 2 in the two-party setup in terms of communication. Multipars is the first actively secure N-party protocol over Z2k that is based on linear homomorphic encryption (LHE) in the offline phase (instead of oblivious transfer or somewhat homomorphic encryption in previous works). The strong performance of Multipars relies on a new adaptive packing for BGV ciphertexts that allows us to reduce the parameter size of the encryption scheme and the overall communication cost. Additionally, we use modulus switching for further size reduction, a new type of enhanced CPA security over Z2k, a truncation protocol for Beaver triples, and a new LHE-based offline protocol without sacrificing over Z2k. We have implemented Multipars and therewith provide the fastest preprocessing phase over Z2k. Our evaluation shows that Multipars offers at least a factor of 8 lower communication costs and up to a factor of 15 faster runtime in the WAN setting compared to the currently best available actively secure MPC implementation over Z2k.","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"67 9","pages":"1932"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140795354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Jang, Dukyoung Kim, Yujin Oh, Sejin Lim, Yujin Yang, Hyunji Kim, Hwajeong Seo
Security vulnerabilities in the symmetric-key primitives of a cipher can undermine the overall security claims of the cipher. With the rapid advancement of quantum computing in recent years, there is an increasing effort to evaluate the security of symmetric-key cryptography against potential quantum attacks. This paper focuses on analyzing the quantum attack resistance of AIM, a symmetric-key primitive used in the AIMer digital signature scheme. We present the first quantum circuit implementation of AIM and estimate its complexity (such as qubit count, gate count, and circuit depth) with respect to Grover’s search algorithm. For Grover’s key search, the most important optimization metric is depth, especially when considering parallel search. Our implementation gathers multiple methods for a low-depth quantum circuit of AIM in order to reduce the Toffoli depth and full depth (such as the Karatsuba multiplication and optimization of inner modules; Mer, LinearLayer).
{"title":"Quantum Implementation of AIM: Aiming for Low-Depth","authors":"K. Jang, Dukyoung Kim, Yujin Oh, Sejin Lim, Yujin Yang, Hyunji Kim, Hwajeong Seo","doi":"10.3390/app14072824","DOIUrl":"https://doi.org/10.3390/app14072824","url":null,"abstract":"Security vulnerabilities in the symmetric-key primitives of a cipher can undermine the overall security claims of the cipher. With the rapid advancement of quantum computing in recent years, there is an increasing effort to evaluate the security of symmetric-key cryptography against potential quantum attacks. This paper focuses on analyzing the quantum attack resistance of AIM, a symmetric-key primitive used in the AIMer digital signature scheme. We present the first quantum circuit implementation of AIM and estimate its complexity (such as qubit count, gate count, and circuit depth) with respect to Grover’s search algorithm. For Grover’s key search, the most important optimization metric is depth, especially when considering parallel search. Our implementation gathers multiple methods for a low-depth quantum circuit of AIM in order to reduce the Toffoli depth and full depth (such as the Karatsuba multiplication and optimization of inner modules; Mer, LinearLayer).","PeriodicalId":508905,"journal":{"name":"IACR Cryptol. ePrint Arch.","volume":"46 17","pages":"337"},"PeriodicalIF":0.0,"publicationDate":"2024-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140376901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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