Lattice-based Ring Research Articles

Lattice-based ring signcryption scheme for smart healthcare management

Lattice-based ring signcryption scheme for smart healthcare management

Secure and efficient vehicle data downloading scheme with privacy-preserving in VANETs

Data downloading is a basic data transfer requirement in VANETs. Cooperation data downloading can use all V2C, V2I and V2V communications to improve the data downloading efficiency. Security and identity privacy preserving of data downloading should be paid more attention to protect the required vehicle. Otherwise, the data and identity information leakages would lead to immeasurable loss. To address these challenges, we propose a lattice-based secure vehicle data downloading scheme with privacy-preserving for VANETs. The vehicle request message authentication and identity privacy of the vehicle are achieved by a designed lattice-based ring signature. We prove that the proposed scheme is strong unforgeable and unconditional privacy preserving in the random oracle model. The request data also is encrypted by a symmetric encryption algorithm to achieve the data confidentiality. Moreover, thanks to the post-quantum security of the lattice-based cryptographic tools, the proposed data downloading also can defend against the quantum attacks. At the same time, cooperation data downloading also can be used in this paper to improve the effects of data downloading. Performance comparison and analysis shows that the proposed scheme shares some advantages with respect to the space and computation efficiency. The main character of the proposed scheme is that the impact of the vehicle ring group number on both the computation and space efficiency is effective controlled, such as the fixed signature length for any ring group size. As a result, the bandwidth and computation resources of VANETs can be saved by using the proposed scheme. We also simulate the proposed scheme by NS-3 which shows the average download success ratio is always within the interval [95%−100%] and cooperative downloading can improve the downloading efficiency by 86%.

Lattice-based ring signcryption for consortium blockchain

Ring signcryption with no group administrator satisfies the decentralization and blockchain anonymity. In this article, we construct new lattice-based ring signcryption scheme suitable for consortium blockchain (CB-LRSCS), in which the smart contract controls the process of signcryption and unsigncryption to make the system be fair and reliable. CB-LRSCS can protect the user privacy by reducing the connection between blockchain and user information, and it satisfies the reliability in ethereum environment. CB-LRSCS also has the characteristics of high efficiency, anti-quantum, anti-forgery, confidentiality and unconditional anonymity, and it can be applied in the electronic finance system.

Zero-Knowledge Arguments for Lattice-Based Accumulators: Logarithmic-Size Ring Signatures and Group Signatures Without Trapdoors

An accumulator is a function that hashes a set of inputs into a short, constant-size string while preserving the ability to efficiently prove the inclusion of a specific input element in the hashed set. It has proved useful in the design of numerous privacy-enhancing protocols, in order to handle revocation or simply prove set membership. In the lattice setting, currently known instantiations of the primitive are based on Merkle trees, which do not interact well with zero-knowledge proofs. In order to efficiently prove the membership of some element in a zero-knowledge manner, the prover has to demonstrate knowledge of a hash chain without revealing it, which is not known to be efficiently possible under well-studied hardness assumptions. In this paper, we provide an efficient method of proving such statements using involved extensions of Stern’s protocol. Under the Small Integer Solution assumption, we provide zero-knowledge arguments showing possession of a hash chain. As an application, we describe new lattice-based group and ring signatures in the random oracle model. In particular, we obtain: (i) the first lattice-based ring signatures with logarithmic size in the cardinality of the ring and (ii) the first lattice-based group signature that does not require any GPV trapdoor and thus allows for a much more efficient choice of parameters.

Compressed Zero-Knowledge Proofs for Lattice-Based Accumulator

Abstract The lattice-based cryptographic accumulators, which enable short zero-knowledge arguments of membership, have numerous applications in post-quantum privacy-preserving protocols. However, most efficient quantum-safe zero-knowledge arguments are PCP-based systems and rely on non-falsifiable assumptions. For non-PCP-based constructions using the state-of-the-art techniques on compressing lattice-based zero-knowledge proofs, the concrete size of the resulting proof for accumulators with $2^{32}$ members is at least 500 KB. In this paper, we propose a compact non-PCP zero-knowledge proof for the lattice-based Merkle-tree, which leads to an efficient post-quantum cryptographic accumulator. The complexity of our construction is logarithmic in $l\cdot n_{s}$, where $l$ and $n_{s}$ denote the depth of the underlying Merkle-tree and the size of a node, respectively, and the concrete size is only $143.7\ $KB when $l=32$. In particular, we provide an improved lattice-based Bulletproof with efficient knowledge extraction, which allows large challenge space but small soundness slack. Furthermore, the amortized technique can be applied to the Bulletproof without breaking the knowledge soundness due to our improved knowledge extraction. As a direct application, we present a practical lattice-based ring signature, which can achieve logarithmical signing/verifying computational complexity with the number of the ring, while the state-of-the-art constructions (CRYPTO 21) have linear computational complexity.

Efficient Lattice-Based Ring Signature Scheme without Trapdoors for Machine Learning.

Machine learning (ML) and privacy protection are inseparable. On the one hand, ML can be the target of privacy protection; on the other hand, it can also be used as an attack tool for privacy protection. Ring signature (RS) is an effective way for privacy protection in cryptography. In particular, lattice-based RS can still protect the privacy of users even in the presence of quantum computers. However, most current lattice-based RS schemes are based on a strong trapdoor like hash-and-sign, and in such constructions, there is a hidden algebraic structure, that is, added to lattice so that the trapdoor shape is not leaked, which greatly affects the computational efficiency of RS. In this study, utilizing Lyubashevsky collision-resistant hash function over lattice, we construct an RS scheme without trapdoors based on ideal lattice via Fiat‒Shamir with aborts (FSwA) protocol. Regarding security, the proposed scheme satisfies unconditional anonymity against chosen setting attacks (UA-CSA), which is stronger than anonymity against full key exposure (anonymity-FKE), and moreover, our scheme satisfies unforgeability with respect to insider corruption (EU-IC). Regarding computational overhead, compared with other RS schemes that satisfy the same degree of security, our scheme has the highest computational efficiency, the signing and verification time costs of the proposed scheme are obviously better than those of other lattice-based RS schemes without trapdoors, which is more suitable for ML scenarios.

An Improved Lattice-Based Ring Signature With Unclaimable Anonymity in the Standard Model

Abstract Ring signatures enable a user to sign messages on behalf of an arbitrary set of users, called the ring, without revealing exactly which member of that ring actually generated the signature. The signer-anonymity property makes ring signatures have been an active research topic. Recently, Park and Sealfon (PS; CRYPTO’19) presented an important anonymity notion named signer-unclaimability and constructed a lattice-based ring signature scheme with unclaimable anonymity in the standard model; however, it did not consider the unforgeable w.r.t. adversarially chosen-key attack (the public key ring of a signature may contain keys created by an adversary) and the signature size grows quadratically in the size of ring and message. In this work, we propose a new lattice-based ring signature scheme with unclaimable anonymity in the standard model. In particular, our work improves the security and efficiency of PS work, which is unforgeable w.r.t. adversarially chosen-key attack, and the ring signature size grows linearly in the ring size.

Anti-Quantum Lattice-Based Ring Signature Scheme and Applications in VANETs.

Message authentication is crucial because it encourages participants to accept countermeasures and further transmit messages to legitimate users in a network while maintaining the legitimacy of the identity of network members. An unauthorized user cannot transmit false messages to a given network. Although traditional public key cryptography is suitable for message authentication, it is also easy to manage and generate keys, and, with the expansion of an entire network, the system needs a lot of computing power, which creates additional risks to network security. A more effective method, such as ring signature, can realize this function and guarantee more security. In this paper, we propose an anti-quantum ring signature scheme based on lattice, functionality analysis, and performance evaluation to demonstrate that this scheme supports unconditional anonymity and unforgeability. After efficiency analysis, our scheme proved more effective than the existing ring signature schemes in processing signature generation and verification. The proposed scheme was applied to VANETs that support strong security and unconditional anonymity to vehicles.

Lattice-Based Ring Signature with Linking-Based Revocation for Industrial Internet of Things

Ring signature augmented by revocation with controlled linkability is proposed. The possibility of using this approach in the Smart Grid as an example of Industrial Internet of Things systems is discussed.

Efficient Lattice-Based Ring Signature for Message Authentication in VANETs

In this article, we propose an efficient lattice-based ring signature scheme for message authentication in vehicular ad-hoc networks (VANETs). It provides unconditional identity privacy preservation, message authentication, and location privacy for the sender vehicle. The authentication of messages is extremely vital as it gives motivation for vehicles to accept, act, and further transmit messages to other vehicles in the network as well as remain a member of the network. Any unauthorized vehicle cannot transmit fraud messages into the network if messages are authenticated. The public key cryptography-based methods are more relevant for message authentication because of their easy key management and local derivation of keys. However, they add complexity to the whole network and require significant storage and computational power. Also, the predictable mobility characteristics of vehicles moving on the road make them vulnerable to tracking. This requires an additional mechanism to preserve location privacy. The proposed scheme provides unconditional identity privacy and location privacy. It is more efficient than the existing ring signature schemes in case of signature generation and verification process. Theoretical analysis and experimental results show that the proposed scheme provides security and unconditional privacy to vehicles in VANETs.

A Comparison of Security and its Performance for Key Agreements in Post-Quantum Cryptography

Nowadays, we are surrounded by devices collecting and transmitting private information. Currently, the two main mathematical problems that guarantee security on the Internet are the Integer Factorization Problem and the Discrete Logarithm Problem. However, Shor’s quantum algorithm can easily solve both problems. Therefore, research into cryptographic algorithms that run in classical computers and are resistant to quantum computers is extremely necessary. This area is known as post-quantum cryptography and usually studies asymmetric cryptography. By means of asymptotic analysis, the purpose of this paper is to provide an evaluation of security and its performance for the types of cryptographic systems considered safe against quantum attacks in the second-round NIST Post-Quantum Standardization Process, namely isogeny cryptosystems based on supersingular elliptic curves, error correction code-based encryption system, and lattice-based ring learning with errors. We performed a security comparison of Key Agreements protocols based on these three post-quantum cryptographic primitives and compared them with Discrete Logarithm Problem and Integer Factorization Problem. The comparison of security and its performance is presented by security level, the former by complexity analyses to achieve theoretical minimum key sizes, and the latter by simulation to assess a practical performance comparison. In the complexity analysis, as we increase the security level and then the size of the cryptographic keys increases, techniques based on isogeny outperform all other post-quantum algorithms in relation to key sizes at practical security level. In the performance comparison, the results show that the code-based protocol presents the best results among the others.

Efficient Ring Signature Scheme Without Random Oracle from Lattices

Among post-quantum alternatives, latticebased cryptography is the most promising one, due to its simple operations, reduction from aver-age-case to worstcase hardness, and supporting of rich functionalities. Ring signature enables a user to sign anonymously on behalf of an adaptively chosen group, and has multiple applications in anonymous e-voting, anonymous authentication, whistle blowing etc. However, most lattice-based ring signature schemes were constructed in the random oracle model from lattice basis delegation and they suffer large verification key sizes as a common disadvantage. This work proposes an efficient ring signature scheme from lattice basis delegation without random oracle based on the extended split-SIS problem, whose security is approximately as hard as the worst-case SIVP problem. Our scheme is proved to be anonymous and existentially unforgeable under latticebased assumptions. Finally, the verification key size is significantly reduced to a small constant, instead of increasing linearly with the number of ring members.

Lattice-based identity-based ring signature without trapdoors

So far, most ring signature schemes rely on hard number theory problems, such as discrete logarithm, bilinear pairings and so on. Unfortunately, the above underlying number theory problems will be solvable in the post quantum era. Lattice-based cryptography is a hotspot of research recently, due to its implementation simplicity and provable security reductions. When the hash-and-sign signature scheme was constructed based on the hardness of worst-case lattice problems, provably secure lattice-based ring signature schemes were finally constructed. However, the hash-and-sign ring signatures were rather inefficient (with megabytes long signatures). In this paper, we propose an alternative method for constructing lattice-based and identity-based ring signature scheme which does not use the hash-and-sign methodology. In the random oracle model, the proposed signature scheme based on the problem in general lattices is unforgeable and holds anonymity. Compared with the previous instantiations of the hash-and-sign ring signature schemes, the lengths of secret key, public key and signatures in the proposed scheme are much shorter. The signing algorithm is quite simple, with matrix-vector multiplications and rejection samplings.

Lattice-based identity-based ring signature without trapdoors

Lattice-based identity-based ring signature without trapdoors

Lattice-based ring signature scheme under the random oracle model

On the basis of the signatures scheme without trapdoors from lattice, which is proposed by Vadim Lyubashevsky in 2012, we present a new ring signature scheme from lattice. The proposed ring signature scheme is an extension of the signatures scheme without trapdoors. We proved that our scheme is strongly unforgeable against adaptive chosen message in the random oracle model, and proved that the security of our scheme can be reduced to the hardness of the small integer solution (SIS) problem by rejection samplings. Compared with the existing lattice-based ring signature schemes, our new scheme is more efficient and with shorter signature length.

Lattice-based ring signature scheme under the random oracle model

On the basis of the signatures scheme without trapdoors from lattice, which is proposed by Vadim Lyubashevsky in 2012, we present a new ring signature scheme from lattice. The proposed ring signature scheme is an extension of the signatures scheme without trapdoors. We proved that our scheme is strongly unforgeable against adaptive chosen message in the random oracle model, and proved that the security of our scheme can be reduced to the hardness of the small integer solution (SIS) problem by rejection samplings. Compared with the existing lattice-based ring signature schemes, our new scheme is more efficient and with shorter signature length.

Improved lattice-based ring signature schemes from basis delegation

Ring signature enables the members to sign anonymously without a manager, it has many online applications, such as e-voting, e-money, whistle blowing etc. As a promising post-quantum candidate, lattice-based cryptography attracts much attention recently. Several efficient lattice-based ring signatures have been naturally constructed from lattice basis delegation, but all of them have large verification key sizes. Our observation finds that a new concept called the split-small integer solution (SIS) problem introduced by Nguyen et al. at PKC'15 is excellent in reducing the public key sizes of lattice-based ring signature schemes from basis delegation. In this research, we first define an extended concept called the extended split-SIS problem, and then prove that the hardness of the extended problem is as hard as the approximating shortest independent vectors problem (SIVP) problem within certain polynomial factor. Moreover, we present an improved ring signature and prove that it is anonymous and unforgeable against the insider corruption. Finally, we give two other improved existing ring signature schemes from lattices. In the end, we show the comparison with the original scheme in terms of the verification key sizes. Our research data illustrate that the public key sizes of the proposed schemes are reduced significantly.

Strongly Unforgeable Ring Signature Scheme from Lattices in the Standard Model

In a ring signature scheme, a user selects an arbitrary ring to be able to sign a message on behalf of the ring without revealing the signer’s identity. Whistle-blowers especially find this useful. To date, various ring signature schemes have been proposed, all considered to be secure as existentially unforgeable with respect to insider corruption; that is, an adversary who chooses ring-message pairs for which he requests signatures, corrupts honest users, and obtains their signing keys can not produce forgeries for new ring-message pairs. Lattice-based ring signature schemes offer lower computational overhead and security from quantum attacks. In this paper, we offer a lattice-based scheme. We begin by showing that the existing ring signature schemes are not sufficiently secure, because existential unforgeability still permits a signer to potentially produce a new signature on previously signed messages. Furthermore, we show that existing ring signature schemes from lattices are not even existentially unforgeable with respect to insider corruption. We then improve previous schemes by applying, for the first time, the concept of strong unforgeability with respect to insider corruption to a ring signature scheme in lattices. This offers more security than any previous ring signature scheme: adversaries cannot produce new signatures for any ring-message pair, including previously signed ring-message pairs.

Efficient Lattice-Based Ring Signature Scheme

An efficient and secure ring signature scheme has a number of important applications.In this paper,we present a new lattice-based ring signature scheme and prove its security in the standard model.The proposed scheme is strongly unforgeable against adaptive chosen message attacks under the standard small integer solution(SIS) assumption.Compared with the existing lattice-based ring signature schemes without random oracles,our new scheme enjoys shorter signature length,high efficiency and stronger security.

A Lattice-based Ring Signature Scheme from Bonsai Trees

A Lattice-based Ring Signature Scheme from Bonsai Trees