Group signatures allow users to sign messages on behalf of a group without revealing authority is capable of identifying the user who generated it. However, the exposure of the user's signing key will severely damage the group signature scheme. In order to reduce the loss caused by signing key leakage, Song proposed the first forward-secure group signature. If a group signing key is revealed at the current time period, the previous signing key will not be affected. This means that the attacker cannot forge group signatures regarding messages signed in the past. To resist quantum attacks, many lattice-based forward-secure group signatures have been proposed. However, their key-update algorithm is expensive since they require some costly computations such as the Hermite normal form (HNF) operations and conversion from a full-rank set of lattice vectors into a basis. In this paper, we propose the group signature with forward security from lattice. In comparison with previous works, we have several advantages: Firstly, our scheme is more effective since we only need to sample some vectors independently from a discrete Gaussian during the key-update algorithm. Secondly, the derived secret key size is linear instead of quadratic with the lattice dimensions, which is more friendly towards lightweight applications. Anonymous authentication plays an increasingly critical role in protecting privacy and security in the environment where private information could be collected for intelligent analysis. Our work contributes to the anonymous authentication in the post-quantum setting, which has wide potential applications in the IoT environment.
Group signatures allow users to sign messages on behalf of a group without revealing authority is capable of identifying the user who generated it. However, the exposure of the user's signing key will severely damage the group signature scheme. In order to reduce the loss caused by signing key leakage, Song proposed the first forward-secure group signature. If a group signing key is revealed at the current time period, the previous signing key will not be affected. This means that the attacker cannot forge group signatures regarding messages signed in the past. To resist quantum attacks, many lattice-based forward-secure group signatures have been proposed. However, their key-update algorithm is expensive since they require some costly computations such as the Hermite normal form (HNF) operations and conversion from a full-rank set of lattice vectors into a basis. In this paper, we propose the group signature with forward security from lattice. In comparison with previous works, we have several advantages: Firstly, our scheme is more effective since we only need to sample some vectors independently from a discrete Gaussian during the key-update algorithm. Secondly, the derived secret key size is linear instead of quadratic with the lattice dimensions, which is more friendly towards lightweight applications. Anonymous authentication plays an increasingly critical role in protecting privacy and security in the environment where private information could be collected for intelligent analysis. Our work contributes to the anonymous authentication in the post-quantum setting, which has wide potential applications in the IoT environment.
Abstract A forward-secure group signature (FSGS) ensures the unforgeability of signatures in the past time period despite signing secret key is leaked in the current time period. As we know, traditional FSGS schemes are mostly relying on number-theoretic assumptions unable to resist quantum attacks. Therefore, we present an efficient lattice-based fully dynamic (i.e. users can flexibly join or quit the group) forward-secure group signature (DFSGS) by combining an improved version of FSGS scheme proposed by Ling. Based on an efficient zero-knowledge argument, we construct argument of knowledge of the committed value and the plaintext that help with privacy protection. Our DFSGS scheme is proved to be anonymous and forward-secure traceable relying on short integer solution and learning with errors assumptions in random oracle model. Moreover, the lengths of group public key and signature of our DFSGS scheme have been improved, and the length of user secret key has no connection with the quantity of group members.
Anonymous authentication schemes such as group signatures and anonymous credentials are important privacy-protecting tools in electronic communications. The only currently known scheme based on assumptions that resist quantum attacks is the group signature scheme by Gordon et al. (ASIACRYPT 2010). We present a generalization of group signatures called anonymous attribute tokens where users are issued attribute-containing credentials that they can use to anonymously sign messages and generate tokens revealing only a subset of their attributes. We present two lattice-based constructions of this new primitive, one with and one without opening capabilities for the group manager. The latter construction directly yields as a special case the first lattice-based group signature scheme offering full anonymity (in the random-oracle model), as opposed to the practically less relevant notion of chosen-plaintext anonymity offered by the scheme of Gordon et al. We also extend our scheme to protect users from framing attacks by the group manager, where the latter creates tokens or signatures in the name of honest users. Our constructions involve new lattice-based tools for aggregating signatures and verifiable CCA2-secure encryption.
Ring signatures, a novel cryptographic primitive, were introduced by Rivest, Shamir, and Tauman at ASIACRYPT 2001. It allows a member of a group to sign a message on behalf of an ad-hoc group of users, known as a ring, without revealing its identity. Ring signatures, initially introduced for applications such as whistle-blowing and confidential disclosures, have since gained significant relevance and widespread adoption across various domains, including blockchain technologies, ad-hoc networks, anonymous transactions, location-based services, cloud computing platforms, and outsourced computation. However, traditional ring signatures are vulnerable if the signers’ keys are compromised. To resolve this vulnerability, Liu and Wong introduced the notion of forward-secure ring signatures at IJNS 2008. Forward-security ensures that even if a signer’s secret key is compromised, signatures generated in prior time periods remain secure. It significantly reduces the damage caused by secret key exposure, making it crucial for long-term security in applications such as whistle-blowing or anonymous authentication. However, most existing forward-secure ring signature schemes are based on number-theoretic assumptions, making them vulnerable to quantum adversaries. Yu and Wang proposed a quantum-safe forward-secure ring signature scheme at ICICS 2023, and Yu et al. further extended this work in Computer Networks (2025), retaining the same ring signature scheme with forward security. But the scheme suffers from large signatures that grow linearly with the ring size. In this paper, we propose a lattice-based forward-secure ring signature scheme in the quantum random oracle model ( QROM ) that simultaneously achieves security against quantum adversaries and compact signature size. Notably, the signature size is logarithmic in the number of members in the ring, enabling significantly better scalability compared to prior constructions.
Abstract The property that linearly homomorphic signature (LHS) enables linear computation on signed data makes this primitive commonly used to secure the network coding based application against pollution attacks. The security of LHS wholly depends on the security of secret signing keys; once a secret key is compromised, the application system’ security will be broken. However, as relatively insecure mobile devices are increasingly used in network coding application systems, the key exposure issue is becoming more prevalent. On the other hand, with the quantum technology development, some existing LHS schemes based on some traditional number-theoretic primitives are susceptible to quantum cryptanalysis. Hence, facing the dual threats of the exposure of secret keys in reality and the future effiffifficient quantum computers, we integrate forward security into LHS, and present a forward-secure identity-based LHS scheme (FSIBLHS) based on lattice assumptions, which achieves post-quantum security, and even if the current secret key is compromised, the validity of signatures of previous time periods is still guaranteed. We defifine the fifirst security model on forward security of LHS, and prove that the proposed scheme can resist adaptively chosen identity and datasets attack under lattice assumption. Moreover, compared with previous related works, the performance analysis shows that our scheme enjoys a comparable computation cost and has a lower communication cost, and provides higher security and stronger functionality.
Abstract With the rapid growth of online users, protecting user privacy in access control scenarios has become a critical challenge in the field of information security. Group signatures serve as a fundamental cryptographic primitive that enables users to sign on behalf of a group, providing anonymity while supporting traceability of signers. However, traditional group signature schemes, which rely on number-theoretic assumptions vulnerable to quantum algorithms, face significant security threats in the advent of quantum computing. In this paper, we propose a module lattice-based group signature scheme (ML-GS). ML-GS leverages FIPS 204 standard, a recently standardized signature scheme by the National Institute of Standards Technology (NIST), and integrates a dualrejection-sampling signature mechanism with the K-PKE encryption scheme from FIPS 203 standard, forming a “sign-hybrid-encrypt” hybrid structure to ensure both efficiency and traceability. In the key generation phase, we introduce a module Gaussian preimage sampling algorithm that reduces public key size and supports dynamic user enrollment. The security of ML-GS is formally proven in the random oracle model under the Module Learning with Error (MLWE) and Module Short Integer Solution (MSIS) assumptions. Experimental results demonstrate that, compared to existing scheme with equivalent security level, the ML-GS scheme achieves significant improvements in both time and storage overhead.