Efficient Linkable Ring Signature Scheme over NTRU Lattice with Unconditional Anonymity

5G-Vehicle-to-Everything (5G-V2X) supports high-reliability and low latency autonomous services and applications. Proposing an efficient security solution that supports multi-zone broadcast authentication and satisfies the 5G requirement is a critical challenge. In The 3rd Generation Partnership Project (3GPP) Release 16 standard, for Cellular- Vehicle-to-Everything (C-V2X) single-cell communication is suggested to reuse the IEEE1609.2 security standard that utilizes the Public Key Infrastructure (PKI) cryptography. PKI-based solutions provide a high-security level, however, it suffers from high communication and computation overhead, due to the large size of the attached certificate and signature. In this study, we propose a light-weight Multi-Zone Authentication and Privacy-Preserving Protocol (MAPP) based on the bilinear pairing cryptography and short-size signature. MAPP protocol provides three different authentication methods that enable a secure broadcast authentication over multiple zones of large-scale base stations, using a single message and a single short signature. We also propose a centralized dynamic key generation method for multiple zones. We implemented and analyzed the proposed key generation and authentication methods using an authentication simulator and a bilinear pairing library. The proposed methods significantly reduce the signature generation time by 16 times–80 times, as compared to the previous methods. Additionally, the proposed methods significantly reduced the signature verification time by 10 times–16 times, as compared to the two previous methods. The three proposed authentication methods achieved substantial speed-up in the signature generation time and verification time, using a short bilinear pairing signature.

In order to meet the need of source authentication in a wireless sensor network composed of IRIS nodes, this paper presents the implementation and performance analysis of the elliptic curve digital signature algorithm (ECDSA) on IRIS nodes. We choose 7 kinds of optimization algorithms for ECDSA to test and compare their performance further. By turning these optimizations on or off, we compare their ROM/RAM consumption, initialization time, signature generation time and signature verification time.

In this paper, we propose a novel lattice-based linkable ring signature scheme based on the Borromean ring signature. In our scheme, to avoid the extra overhead caused by reject sampling that used in the existing schemes, we use an exact indistinguishable distribution to replace it. Using our method, signature will be successfully generated without repeating, so the size of the signature can be reduced. Furthermore, our scheme can be extended to multiple layers easily. We also propose a lattice-based multilayer linkable ring signature scheme which can be use for transactions with multiple inputs. Then, we prove that our scheme has unforgeability, anonymity, linkability and non-slanderability that a linkable ring signature scheme should have. Efficiency analysis shows that our scheme has a smaller signature size under the same security conditions.

A linkable ring signature allows a user to sign anonymously on behalf of a group while ensuring that multiple signatures from the same user are detected. Applications such as privacy-preserving e-voting and e-cash can leverage linkable ring signatures to significantly improve privacy and anonymity guarantees. To scale to systems involving large numbers of users, short signatures with fast verification are a must. Concretely efficient ring signatures currently rely on a trusted authority maintaining a master secret, or follow an accumulator-based approach that requires a trusted setup.In this work, we construct the first linkable ring signature with both logarithmic signature size and verification that does not require any trusted mechanism. Our scheme, which relies on discrete-log type assumptions and bilinear maps, improves upon a recent concise ring signature called DualRing by integrating improved preprocessing arguments to reduce the verification time from linear to logarithmic in the size of the ring. Our ring signature allows signatures to be linked based on what message is signed, ranging from linking signatures on any message to only signatures on the same message.We provide benchmarks for our scheme and prove its security under standard assumptions. The proposed linkable ring signature is particularly relevant to use cases that require privacy-preserving enforcement of threshold policies in a fully decentralized context, and e-voting.

Aiming at the problem that the fully homomorphic encryption scheme based on single identity cannot satisfy the homomorphic operation of ciphertext under different identities, as well as the inefficiency of trapdoor function and the complexity of sampling algorithm, an improved lattice MIBFHE scheme was proposed. Firstly, we combined MP12 trapdoor function with dual LWE algorithm to construct a new IBE scheme under the standard model, and prove that the scheme is IND-sID-CPA security under the selective identity. Secondly, we used the eigenvector method to eliminate the evaluation key, and transform the above efficient IBE scheme into a single identity IBFHE scheme to satisfy the homomorphic operation. Finally, we improved the ciphertext extension method of CM15 and constructed a new Link-mask system that supports the transformation of IBFHE scheme under the standard model, and then, converted the above IBFHE scheme into MIBFHE scheme based on this system. The comparative analysis results showed that the efficiency of this scheme is improved compared with similar schemes in the trapdoor generation and preimage sampling, and the dimension of lattice and ciphertext size are significantly shortened.

In Eurocrypt 2007, Camenisch, Hohenberger and Pedersen introduced the notion of multi-signer batch verification and proposed several efficient and practical batch verification schemes for signatures, including a very efficient batch verification scheme for a multi-signer setting without random oracles. This scheme is the most efficient in comparison with other existing schemes, but it can be applied only to the multi-signer setting. We observe that amongst all existing batch verification schemes, the fastest scheme for a single-signer setting is based on the BLS short signature whose proof need resort to random oracles. It is clear that batch verification for a single-signer setting is as important as for multi-signer scenarios in some applications, especially where the system has only a single signer, such as a secure time-stamping server or a certificate generation server. However, to our knowledge, the efficient batch verification of short signatures in a single-signer setting without random oracles is a challenging open problem. In this paper, we propose a new signature scheme from Gentry IBE that is as efficient as the BLS short signature scheme in batch verification. We are able to prove its security without random oracles. Our signature is approximately 320 bits in length, and a verification requires only two pairings for verifying n signatures from a single signer.

Efficient heterogeneous signcryption scheme based on Edge Computing for Industrial Internet of Things

A ring signature scheme is a group signature scheme but with no group manager to setup a group or revoke a signer's identity. It allows members of a group to sign messages such that the resulting signatures do not reveal the identities of the group members who actually created these signatures (anonymity) and no one can tell if two signatures are created by the same signer (unlinkability). Furthermore, the formation of a group is spontaneous. Diversion group members (non-signers) can be totally unaware of being conscripted to the group. The notion of linkable ring signature, introduced by Liu et al. in 2004, also provides signer anonymity and spontaneity, but at the same time, allows anyone to determine whether two signatures have been issued by the same group member (linkability). In this paper, we propose a suite of enhanced security models and show that they capture stronger notions of signer anonymity and linkability than the original ones proposed by Liu et al. in 2004. We also propose a generic approach for constructing a linkable ring signature scheme. The generic approach leads us to the construction of two efficient polynomial-structured schemes and one type-restricted separable scheme. The separable scheme allows group members to have different sets of DL (discrete logarithm) domain parameters. All schemes are shown secure under the enhanced security models defined in this paper.

Efficient incremental authentication for the updated data in fog computing

Cryptanalysis and improvement of a certificateless aggregate signature scheme

One of the most efficient post-quantum signature schemes is Rainbow whose hardness is based on the multivariate quadratic polynomial (MQ) problem. ELSA, a new multivariate signature scheme proposed at Asiacrypt 2017, has a similar construction to Rainbow. Its advantages, compared to Rainbow, are its smaller secret key and faster signature generation. In addition, its existential unforgeability against an adaptive chosen-message attack has been proven under the hardness of the MQ-problem induced by a public key of ELSA with a specific parameter set in the random oracle model. The high efficiency of ELSA is derived from a set of hidden quadratic equations used in the process of signature generation. However, the hidden quadratic equations yield a vulnerability. In fact, a piece of information of these equations can be recovered by using valid signatures and an equivalent secret key can be partially recovered from it. In this paper, we describe how to recover an equivalent secret key of ELSA by a chosen message attack. Our experiments show that we can recover an equivalent secret key for the claimed 128-bit security parameter of ELSA on a standard PC in 177 s with 1326 valid signatures.

To design an efficient post-quantum linearly homomorphic signature scheme, using the pre-image sampling function, a lattice-based linearly homomorphic signature scheme over a binary field is proposed in this paper. Linear homomorphism is achieved through the homomorphism of the lattice-based hash function used in the proposed signature scheme. It is shown that the proposed scheme satisfies the privacy property. Based on the hardness of the short integer solution problem, the proposed scheme is unforgeable against the type 1 and type 2 adversaries in the random oracle model. Moreover, compared with a presented linearly homomorphic signature scheme in 2011, the proposed scheme has some advantages with respect to the public key size, signature length and computational cost.

The notion of certificateless cryptography is aimed to eliminate the use of certificates in traditional public key cryptography and also to solve the key-escrow problem in identity-based cryptography. Many kinds of security models have been designed for certificateless cryptography and many new schemes have been introduced based on the correspondence of the security models. In generally speaking, a stronger security model can ensure a certificateless cryptosystem with a higher security level, but a realistic model can lead to a more efficient scheme. In this paper, we focus on the efficiency of a certificateless signature (CLS) scheme and introduce an efficient CLS scheme with short signature size. On one hand, the security of the scheme is based on a realistic model. In this model, an adversary is not allowed to get any valid signature under false public keys. On the other hand, our scheme is as efficient as BLS short signature scheme in both communication and computation and, therefore, turns out to be more efficient than other CLS schemes proposed so far. We provide a rigorous security proof of our scheme in the random oracle model. The security of our scheme is based on the k-CAA hard problem and a new discovered hard problem, namely the modified k-CAA problem. Our scheme can be applied to systems where signatures are typed in by human or systems with low-bandwidth channels and/or low-computation power.

WSNs are one of the important components in the Internet of Things (IoTs), since they enable gathering and transmitting of data to the cloud server via the Internet medium. Designing an efficient secure cryptography scheme for the IoTs is a challenging task, since sensor node is a resource-constrained device. In this paper, an authentication key agreement scheme is proposed to build a secure channel between WSNs and a cloud server in the IoTs. The proposed scheme has two properties: (1) it has a lightweight computation, and (2) it provides various security properties of key agreement. In addition, it is proven to be secure under computation Diffe–Hellman assumption in the random oracle model. AKAIoTs is implemented using Contiki OS and use Z1 emulator to evaluate time overhead and memory usage. Three different curves; “BN-P158”, “SECG-P160” and “NIST-P192” are used. The implementation results verify that, the proposed scheme is computationally efficient and memory usage between 51 and 52% from total memory of ROM, and between 59 and 62% from total memory of RAM for three different security levels. As a result, curve SECG-P160 might be a good choice to supply security for the IoTs devices, since it consumes reasonable time which result in less power consumption than curve NIST-P192 and more secure than curve BN-P158. Compared with existing relevant schemes, the proposed AKAIoTs is efficient in terms of energy consumption. Moreover, two application scenarios are given to show how the proposed scheme can be applied in the IoTs applications.

SummaryIn a short signature scheme, the length of signature is much smaller than that of the general signature. Short signatures are widely used in low‐computation, low‐storage, and low‐bandwidth communication environments. The proof of security of all certificateless short signature schemes currently known is given in the random oracle model. In this paper, a new certificateless short signature scheme is constructed, and it is proved to be unforgeable in the standard model. Taken into account the computation costs, the scheme performs only one pairing operation, so it is more efficient than previous ones.