Constant-size Signature Research Articles

Efficient code-based fully dynamic group signature scheme

Code-based group signature is an important research topic in recent years. Since the pioneering work by Alamélou et al.(WCC 2015), several other schemes have been proposed to provide improvements in security, efficiency and functionality. However, most existing constructions work only in the static setting where the group population is fixed at the setup phase. Only a few schemes address partially dynamic, which can realize only one of users enrollment or revocation.In this work, we provide an efficient code-based fully dynamic group signature (FDGS) scheme, i.e., users have flexibility when joining and leaving the group. Specifically, to upgrade the scheme into a fully dynamic group signature, we first add a dynamic ingredient into the static 2-RNSD Merkle-tree accumulator (ASIACRYPT 2019), then create a simple rule and utilize the Stern-like zero-knowledge protocol to handle users enrollment and revocation efficiently (i.e., without resetting the whole tree). Moreover, our solution is the first exploration of code-based FDGS with constant signature size.

A certificateless ring signature scheme based on lattice

SummaryFor the problems that ring signature needs key escrow, has some security risks, and cannot avoid malicious key generation center (KGC) in the post‐quantum era, we design a certificateless ring signature scheme based on lattice (L‐CRSS). In our scheme, the bimodal Gaussian distribution is used to improve the security and efficiency. Compared with the previous ring signature scheme based on lattice, our design does not need key escrow, does not disclose the signer's identity, can avoid malicious KGC, achieves the constant signature size, and has higher security and efficiency in the post‐quantum era. Finally, under random oracle model (ROM), we prove that our scheme is anonymous against the full‐key exposure, and existentially unforgeable against adaptive chosen message attacks (EUF‐CMA).

Secure aggregate signature scheme for smart city applications

With the recent advances in technology, smart cities are rapidly earning momentum. To provide better lives, smart cities should host several applications to increase the efficiency and accessibility of services. Since these services involve the conveyance of significant data among the smart cities’ cloud and the dwellers over the Internet, security and privacy are critical. This paper proposes an authentication protocol with a full aggregation signature to secure the smart city applications. A certificate-less aggregate signature (CLAS) is used for smart city real applications such as secure routing and database outsourcing. The proposed CLAS achieves message authentication, user anonymity, constant signature size, unlinkability, and is resistant to replay attacks. Also, we have proved that the proposed scheme is resistant to all malicious adversaries. Finally, the performance evaluation results show that the proposed CLAS performs better than existing relevant schemes.

Evaluation of Hazards and Operability Study for Optimization Operation of Industrial Processes

With the recent advances in technology, smart cities are rapidly earning momentum thanks to the quality of citizens' life that smart cities help improve. To provide better lives, smart cities should host several applications to increase the efficiency and accessibility of services. Since these services involve the conveyance of significant data among the smart cities' cloud and the dwellers over the Internet, security and privacy are critical. This paper proposes an authentication protocol with a full aggregation signature to secure the smart city applications. A certificateless aggregate signature (CLAS) is used for smart city real applications such as secure routing and database outsourcing. The proposed CLAS achieves message authentication, user anonymity, constant signature size, unlinkability, and is resistant to replay attacks. Also, we have proved that the proposed scheme is resistant to all malicious adversaries. Finally, the performance evaluation results show that the proposed CLAS performs better than existing relevant schemes.

A constant-size lattice-based partially-dynamic group signature scheme in quantum random oracle model

A group signature allows a group member who signs the message on behalf of the other group members. Any recipient also verifies the signature without knowing the signer. However, it is possible to reveal the signer’s identity since the group signatures have the tracing mechanism. In general, the group signature size increases the number of group members. However, the schemes are also proposed with the constant signature size. On the other hand, the security of some schemes are based on the discrete logarithm and factorization problems while some schemes which are secure against quantum attacks are proposed. To the best of our knowledge, the signature scheme in the group concept has not been proposed on lattices in quantum oracles. In this paper, we propose a new constant-size and partially-dynamic group signature scheme on lattice assumptions. We combine the Dilithium signature scheme, a Stern-like zero-knowledge scheme and Regev’s encryption scheme. We give a zero-knowledge argument system for our proposed scheme and security analysis in the quantum random oracle model. According to the comparison results, the proposed scheme has better size complexity in asymptotic concept.

Efficient Traceable Attribute-Based Signature With Update-Free Revocation For Blockchain

AbstractAttribute-based signature (ABS) allows signers with a set of attributes to sign messages anonymously using a specific signing policy. However, previous schemes suffer from some efficiency issues which are not widely applied on the blockchain. In this paper, we investigate ABS regarding its features and efficiency in the blockchain setting and provide our solution correspondingly. To solve the revocation problem of ABS in a more efficient manner, we introduce the update-free revocation function. Instead of the passive attribute expiration approaches, we take the active method to ensure that no parameter updates are required by users after the execution of the revocation function. In terms of efficiency, we first address the problem that the signer has to provide proof for all attributes in the predicate for privacy, which is one of the efficiency bottlenecks for ABS. By taking advantage of the blockchain architecture, we propose a new solution which can achieve the constant signature size and verification cost, while the signing cost can be greatly reduced. The corresponding security levels are satisfied according to their strict criteria. A generic construction as well as an instantiation are provided which is provably secure in the standard model satisfying the newly defined formal security definitions. Finally, a purer primitive is discussed.

A fine-grained anonymous handover authentication protocol based on consortium blockchain for wireless networks

Given the ubiquitous nature of wireless networks in today's society, protecting users' information and identity during handover authentication is paramount. Mobile network operators hope to implement a more flexible and fine-grained authentication to provide better and safer services. In this paper, we propose a new multi-attribute authority attribute-based signature (MA-ABS) scheme that has a constant-size signature. More specifically, we propose an anonymous handover authentication protocol that uses MA-ABS and consortium blockchain. This new protocol not only has fine-grained access control, but it protects the user's privacy and ensures an efficient and private handover.

LH-ABSC: A Lightweight Hybrid Attribute-Based Signcryption Scheme for Cloud-Fog-Assisted IoT

One of the best ways to deal with the massive data generated by the Internet of Things (IoT) is storing them in the cloud. However, outsourced storage raises some security and privacy issues, such as data leaking and illegal access. The attribute-based signcryption (ABSC) is one of the most promising approaches which can ensure the confidentiality and authenticity of data simultaneously. Nonetheless, it not only inherits the fine-grained access control but also the heavy computational cost which is intolerable for most resource-limited IoT devices. In this article, we propose lightweight hybrid-policy ABSC (LH-ABSC), a lightweight ABSC scheme which adopts ciphertext-policy encryption (CPABE) and key-policy attribute-based signature (KPABS). Ciphertext-policy attribute-based signature leads the decision making that who can decrypt to the data owners directly. Meanwhile, the signature is related with data owners' attribute set which can be used to testify the authenticity of data. In particular, LH-ABSC has constant signature size and satisfies public verification which is deeply important for IoT devices. Moreover, LH-ABSC outsources most computing overhead to fog nodes, including signature, verify, and decryption. Comprehensive theoretical analyses, such as confidentiality, unforgeability, and verifiability, are provided. Also, the selective chosen ciphertext security, the selective chosen message security, and signers anonymity are achieved.

Constant-size ring signature scheme using multilinear maps

Ring signature is a group-oriented digital signature with anonymity. Most of existing ring signature schemes use bilinear pairings, are provably secure in the random oracles, or are linear signature size to the number of ring member. In this paper, we use multilinear maps, which have been widely used to construct many novel cryptographic primitives recently, to present a ring signature scheme with constant signature size. The proposed scheme is proven to be anonymous against full key exposure and unforgeable against chosen-subring attacks based on the multilinear computational Diffie-Hellman assumption in the standard model. Furthermore, our scheme has the advantage of tighter security reduction by using an optimal security reduction technique.

Constant-size ring signature scheme using multilinear maps

Ring signature is a group-oriented digital signature with anonymity. Most of existing ring signature schemes use bilinear pairings, are provably secure in the random oracles, or are linear signature size to the number of ring member. In this paper, we use multilinear maps, which have been widely used to construct many novel cryptographic primitives recently, to present a ring signature scheme with constant signature size. The proposed scheme is proven to be anonymous against full key exposure and unforgeable against chosen-subring attacks based on the multilinear computational Diffie-Hellman assumption in the standard model. Furthermore, our scheme has the advantage of tighter security reduction by using an optimal security reduction technique.

A Constant-Size Signature Scheme with a Tighter Reduction from the CDH Assumption

A Constant-Size Signature Scheme with a Tighter Reduction from the CDH Assumption

Predicate signatures from pair encodings via dual system proof technique

Abstract Recently, Attrapadung (Eurocrypt 2014) proposed a generic framework for fully (adaptively) secure predicate encryption (PE) based on a new primitive, called pair encodings. The author shows that if the underlying pair encoding scheme is either perfectly secure or computationally (doubly-selectively) secure, then the PE scheme will be fully secure. Although the pair encodings were solely introduced for PE, we show that these can also be used to construct predicate signatures, a signature analogue of PE. More precisely, we propose a generic construction of predicate signature (PS) from pair encoding schemes. Our construction provides unconditional signer privacy, and unforgeability in the adaptive model. Thereafter, we instantiate many PS schemes with new results, e.g., the first practical PS schemes for regular languages, the first attribute-based signature (ABS) scheme with constant-size signatures in the adaptive model, unbounded ABS with large universes in key-policy flavor, etc.

Identity-based key-insulated aggregate signature scheme

Private key exposure can be the most devastating attack on cryptographic schemes; as such exposure leads to the breakage of security of the scheme as a whole. In the real world scenario, this problem is perhaps the biggest threat to cryptography. The threat is increasing with users operating on low computational devices (e.g. mobile devices) which hold the corresponding private key for generating signatures. To reduce the damage caused by the key exposure problem in aggregate signatures and preserve the benefits of identity-based (ID-based) cryptography, we hereby propose the first key-insulated aggregate signature scheme in ID-based setting. In this scheme the leakage of temporary private keys will not compromise the security of all the remaining time periods. The security of our scheme is proven secure in the random oracle paradigm with the assumption that the Computational Diffie–Hellman (CDH) problem is intractable. The proposed scheme allows an efficient verification with constant signature size, independent of the number of signers.

Constant-Size Structure-Preserving Signatures: Generic Constructions and Simple Assumptions

This paper presents efficient structure-preserving signature schemes based on simple assumptions such as decisional linear. We first give two general frameworks for constructing fully secure signature schemes from weaker building blocks such as variations of one-time signatures and random message secure signatures. They can be seen as refinements of the Even---Goldreich---Micali framework, and preserve many desirable properties of the underlying schemes such as constant signature size and structure preservation. We then instantiate them based on simple (i.e., not q-type) assumptions over symmetric and asymmetric bilinear groups. The resulting schemes are structure-preserving and yield constant-size signatures consisting of 11---14 group elements, which compares favorably to existing schemes whose security relies on q-type assumptions.

Efficient attribute-based signature and signcryption realizing expressive access structures

This paper addresses the open problem of designing attribute-based signature (ABS) schemes with constant number of bilinear pairing operations for signature verification or short signatures for more general policies posed by Gagne et al. in Pairing 2012. Designing constant-size ABS for expressive access structures is a challenging task. We design two key-policy ABS schemes with constant-size signature for expressive linear secret-sharing scheme (LSSS)-realizable monotone access structures. Both the schemes utilize only 3 pairing operations in signature verification process. The first scheme is small universe construction, while the second scheme supports large universes of attributes. The signing key is computed according to LSSS-realizable access structure over signer's attributes, and the message is signed with an attribute set satisfying the access structure. Our ABS schemes provide the existential unforgeability in selective attribute set security model and preserve signer privacy. We also propose a new attribute-based signcryption (ABSC) scheme for LSSS-realizable access structures utilizing only 6 pairings and making the ciphertext size constant. Our scheme is significantly more efficient than existing ABSC schemes. While the secret key (signing key or decryption key) size increases by a factor of number of attributes used in the system, the number of pairing evaluations is reduced to constant. Our protocol achieves (a) ciphertext indistinguishability under adaptive chosen ciphertext attacks assuming the hardness of decisional Bilinear Diffie---Hellman Exponent problem and (b) existential unforgeability under adaptive chosen message attack assuming the hardness of computational Diffie---Hellman Exponent problem. The security proofs are in selective attribute set security model without using any random oracle heuristic. In addition, our ABSC achieves public verifiability of the ciphertext, enabling any party to verify the integrity and validity of the ciphertext.

Structure-Preserving Signatures and Commitments to Group Elements

A modular approach to constructing cryptographic protocols leads to simple designs but often inefficient instantiations. On the other hand, ad hoc constructions may yield efficient protocols at the cost of losing conceptual simplicity. We suggest a new design paradigm, structure-preserving cryptography, that provides a way to construct modular protocols with reasonable efficiency while retaining conceptual simplicity. A cryptographic scheme over a bilinear group is called structure-preserving if its public inputs and outputs consist of elements from the bilinear groups and their consistency can be verified by evaluating pairing-product equations. As structure-preserving schemes smoothly interoperate with each other, they are useful as building blocks in modular design of cryptographic applications. This paper introduces structure-preserving commitment and signature schemes over bilinear groups with several desirable properties. The commitment schemes include homomorphic, trapdoor and length-reducing commitments to group elements, and the structure-preserving signature schemes are the first ones that yield constant-size signatures on multiple group elements. A structure-preserving signature scheme is called automorphic if the public keys lie in the message space, which cannot be achieved by compressing inputs via a cryptographic hash function, as this would destroy the mathematical structure we are trying to preserve. Automorphic signatures can be used for building certification chains underlying privacy-preserving protocols. Among a vast number of applications of structure-preserving protocols, we present an efficient round-optimal blind-signature scheme and a group signature scheme with an efficient and concurrently secure protocol for enrolling new members.

Multi-party concurrent signatures scheme from lattice

Concurrent signatures scheme is an effective way to solve the problem of fair exchange without the help of any trusted third party. Until now, all concurrent signatures are based on traditional cryptosystems, but the emergence of quantum computing poses a severe threat to the security of classic public-key cryptosystems. More and more attentions are being paid to lattice-based cryptosystems, which is one of the candidate cryptosystems against the attacks from quantum computing. In this paper, we present a new formal model of multi-party concurrent signatures scheme and a lattice-based multi-party concurrent signatures scheme. The scheme has comparative advantages in both efficiency and security over the existing concurrent signatures schemes based on traditional cryptosystem. In particular, our scheme is constructed based on constant-size ring signatures, and thus we have solved the open problem: how to construct a multi-party concurrent signatures scheme based on constant-size ring signatures, which was proposed by Tonien et al. 2006.

Secure Outsourced Attribute-Based Signatures

Attribute-based signature (ABS) enables users to sign messages over attributes without revealing any information other than the fact that they have attested to the messages. However, heavy computational cost is required during signing in existing work of ABS, which grows linearly with the size of the predicate formula. As a result, this presents a significant challenge for resource-constrained devices (such as mobile devices or RFID tags) to perform such heavy computations independently. Aiming at tackling the challenge above, we first propose and formalize a new paradigm called Outsourced ABS, i.e., OABS, in which the computational overhead at user side is greatly reduced through outsourcing intensive computations to an untrusted signing-cloud service provider (S-CSP). Furthermore, we apply this novel paradigm to existing ABS schemes to reduce the complexity. As a result, we present two concrete OABS schemes: i) in the first OABS scheme, the number of exponentiations involving in signing is reduced from $O(d)$ to $O(1)$ (nearly three), where $d$ is the upper bound of threshold value defined in the predicate; ii) our second scheme is built on Herranz et al.’s construction with constant-size signatures. The number of exponentiations in signing is reduced from $O(d^2)$ to $O(d)$ and the communication overhead is $O(1)$ . Security analysis demonstrates that both OABS schemes are secure in terms of the unforgeability and attribute-signer privacy definitions specified in the proposed security model. Finally, to allow for high efficiency and flexibility, we discuss extensions of OABS and show how to achieve accountability as well.

Private mutual authentications with fuzzy matching

A private mutual authentication, or unlinkable secret handshake, originally allows two members from the same organisations to anonymously authenticate each other. In this paper, a new privacy-preserving mutual authentication protocol is constructed to achieve fuzzy private matching. The proposed protocol supports more flexible threshold-based appropriate matching under the multiple-groups environment, which is not limited to authenticate between members from the same groups. Our new protocol is constructed from the fuzzy identity-based encryption scheme and constant-size group signature. Without using the random oracle, the new protocol is proved secure by assuming the intractability of the decisional bilinear Diffie-Hellman problems. Compared with previous works, our proposed protocol can adapt to many different applications.

Identity-based threshold ring signature scheme with constant signature size

Identity-based threshold ring signature scheme with constant signature size