With the rapid development of Internet of Things (IoT), biometric-based authentication systems have been widely used for access control. The wide application of biometric recognition systems has brought convenience but also raised privacy and security concerns. When unprotected templates are stolen, it will permanently leak the original biometric data. Therefore, it is important to ensure the security of biometric templates while meeting the real-time device requirements. Motivated by these issues, in this paper, we proposed a scheme based on partial Cake-cutting transformation and spherical hashing to generate cancelable binary face templates. Firstly, with external random parameters, partial Cake-cutting transformation is established to introduce randomness and preserve the relative distance similarity of face features. Then spherical hashing is utilized to encode the face features into protected binary codes. The protected template has the advantages of high entropy value, low storage consumption, and fast generation speed. Extensive experiments conducted on LFW, CFPW, and CASIA-FaceV5 databases along with theoretical analyses indicate that the proposed scheme shows good matching accuracy and strong resistance to various attacks. Besides, the protected templates can achieve equal or even better accuracy than the unprotected counterparts. Furthermore, the proposed scheme also satisfies the requirements of cancelable biometrics, i.e., irreversibility, revocability, and unlinkability.

The Approximate Homomorphic Encryption scheme CKKS offers a distinctive and effective approach to privacy-preserving computation, with significant potential applications in IoT and machine learning domains. Recent advancements have introduced bootstrapping techniques tailored for CKKS, including the EvalMod and EvalRound bootstrapping techniques. These bootstrapping techniques mainly focus on approximate computation of modular reduction functions. However, the approximation of modular functions encounters challenges related to computational efficiency and bootstrapping precision, thus emerging as a major bottleneck in the advancement of bootstrapping techniques. Motivated by these concerns, in this paper, we introduce a novel bootstrapping scheme named EvalComp, which eliminates the need to fit modular functions. Unlike existing approaches, EvalComp constructs a homomorphic rounding function using the Homomorphic Comparison Function (HCF) and thus removes the integer multiples of the modulus$\boldsymbol {q}$from the ciphertext. For$\boldsymbol {N = {2^{9}}}$, EvalComp enhances bootstrapping precision by over 11 bits and computational efficiency by 16.7% compared with the latest EvalMod scheme (JM22). Additionally, compared with the EvalRound scheme (KPK22+), our scheme improves bootstrapping precision by 2-3 bits and computational efficiency by 20.2%. According to the bootstrapping performance comparison criterion, the performance of EvalComp achieves 1.80 times that of JM22 and 1.69 times that of KPK22+.

With the widespread application of biometric, unprotected biometric data is still at risk of serious security and privacy breaches. When large amounts of unprotected biometric data leak, cancelable biometric become a powerfully remedial measure. In this paper, we propose a new method to generate stable and cancelable face templates based on multiple partial Walsh transformations (MPWT) and Simhash. Firstly, multiple partial Walsh matrices generated with random external parameters perform projection transformation on the original real-valued face features, ensuring the irreversibility and unlinkability of the system. Subsequently, the projected features are transformed into discrete binary codes (protected templates) using Simhash. And the random permutation seed ensures the revocability of generated protected template. Furtherly, the protected templates have small storage space and is more suitable for fast comparison but also yields improvements in recognition accuracy compared with several state-of-the-arts. Numerous experiments on CASIA-WebFace, LFW, FEI, and Color FERET databases show that the protected templates are nearly identical to the unprotected ones in the comparison performance. The scheme also meets the requirements of non-invertibility, revocability, unlinkability, as well as resistance for various types of attacks like attacks via record multiplicity, false accepts, brute force and pre-image. Therefore, the proposed methodology strikes a balance between recognition accuracy and security.

With the decreasing size of fingerprint scanners in portable devices, e.g., mobile phone and smart watch, partial fingerprint recognition has become a challenging and urgently needed technique due to the limited features contained in small area as well as the large rotation and translation between query and reference images. Deep learning as a powerful modeling method has advanced the research progress of fingerprint recognition, but it still suffers from the lack of labeled data in the scenario of partial fingerprint matching. In this paper, we propose a novel partial fingerprint verification network (PFVNet) based on spatial transformer network (STN) and the local self-attention mechanism. Our model can be trained end-to-end and learn multi-level fingerprint features automatically. To alleviate the data annotation work, the model is trained in a self-supervision and domain adaptation manner with data generated from large fingerprint image matching. The experimental results compared with other methods on FVC2006 DB1 dataset and in-house datasets (i.e., ZJUPartial database) show that our method achieves state-of-the-art performance, and also robust to different types of scanners.

Cancelable biometrics is a powerful remedy for information leakage caused by the extensive usage of unprotected biometric data. Current measures usually suffer from deteriorated accuracy, which is known as the security–performance tradeoff. Motivated by these concerns, in this article, a novel cancelable fingerprint approach, i.e., Indexing-Min–Max (IMM) hashing, is proposed to securely transform a fixed-length fingerprint feature vector to a discrete index hashed code. IMM hashing is essentially established upon the min–max hash and further strengthened by the integration of the partial Hadamard transform, which alleviates performance deterioration while maintaining a high security level. Extensive experiments on FVC2002 and FVC2004 fingerprint datasets coupled with comprehensive theoretical analyses demonstrate the favorable accuracy and strong anti-attack resilience of the proposed method. Besides, compared to the unprotected counterpart, the matching precision of the protected templates yields little accuracy loss or even improved performance, which means the security–performance tradeoff is well handled. Furthermore, IMM hashing also meets the unlinkability and revocability requisites of cancelable biometrics.

Representing fingerprint templates in binary form can provide outstanding merits compared to the conventional minutiae-based fingerprint recognition system. The existing fixed-length fingerprint feature extraction methods either suffer from redundant feature magnitude or lack of template security. In this letter, we present a compact (128 bytes) and cancelable fingerprint binary codes generation scheme which enables accurate and efficient comparison as well as high security. This binary representation is also available for advanced encryption schemes (e.g., fuzzy commitment). Specifically, a kernel learning-based real-valued fingerprint feature is converted into compact and cancelable binary code via one permutation hashing. A partial Haar transform is deployed to further strengthen the irreversibility of the whole system. Experimental results on six benchmark datasets FVC2002 and FVC2004 coupled with security analysis demonstrate the superiority of the proposed method compared with several state-of-the-arts.

The minutiae set defined by the ISO/IEC 19794‐2 is one of the prevalent feature used in fingerprint recognition systems. Unfortunately, such characteristic of unordered and variable‐sized minutiae information causes a restriction on the operation in some advanced template protection methods (e.g. fuzzy commitment), which usually require an ordered and fixed‐length binary feature representation as the system input. In this study, in order to simultaneously extend the application of fingerprint recognition and provide satisfactory system performance, the authors propose a novel fixed‐length bit‐string conversion framework based on spectral clustering and the proposed newly designed discriminative fingerprint representation called minutia vicinity combined feature (MVCF). The proposed method consists of three stages: (i) the extraction of MVCF, (ii) bit conversion via the spectral clustering algorithm, and (iii) matching. Benefiting from feature invariance, fixed‐length and bit‐oriented coding, merits such as fast matching and decent accuracy are well guaranteed. The performance evaluation is conducted on six publicly available benchmark data sets: FVC2002 DB1, DB2, DB3 and FVC2004 DB1, DB2, DB3 confirms the superiority of the proposed method and suggests the promise of migrating to some other domains (e.g., template protection).

Small‐sized fingerprint sensors, due to the convenience of integration, are widely used in many applications, especially on smart phones. However, the friction ridge information decreases with the reduction of the collected fingerprint area, resulting in degraded recognition performance. Mosaicking fingerprint impressions has been proved to be effective in boosting the recognition accuracy. Nonetheless, the minutiae‐based mosaicking methods do not work well when there is no sufficient number of minutiae in the overlapping area while existing minutia‐free mosaicking methods are not robust to distortion and result in low mosaicking accuracy. In this study, a novel minutia‐free mosaicking algorithm used the coarse‐to‐fine approach is proposed to obtain a larger fingerprint impression from a couple of small‐sized fingerprint impressions. It consists of three stages: an orientation field‐based coarse alignment, a ridge matching‐based fine alignment, and a nonlinear deformation correction with block‐correspondence Thin Plate Spline model. Experimental results on the XDfinger database demonstrate that the proposed method outperforms the other six mosaicking methods in terms of reject‐to‐fuse rate, registration accuracy, and verification performance. Specifically, in the verification scenario, the equal error rate is reduced from 1.98% of a single impression to 0.41% of two impressions mosaicked by the authors' method.

In recent years, palmprint recognition has made great progress and many methods have been put forward. The extraction of robust orientation features and finding efficient matching strategies are two key points for palmprint recognition. Traditional coding methods usually only use a dominant filter response to extract orientation features of palmprint images while not taking into account the other useful filter responses. Without increasing the number of filers, this study presents a modified Competitive Code to extract orientation features more accurately, which makes use of the relation between the filter responses. Besides, a distinctive extended eight‐pixel neighbourhood method is proposed to select the sample points for matching by extracting the local features. At the matching stage, an effective fusion matching scheme with a double‐layer image pyramid is designed to calculate the similarity between two palmprint images. Extensive experiments on four types of public palmprint databases show that the proposed method has excellent performance compared with the other state‐of‐the‐art algorithms.

As a kind of special proxy signature, directed proxy signature can be used to sign messages, such that only the designated verifier can easily verify the validity of the signature while others cannot. At the same time, if necessary, the proxy signer or designated verifier can prove the validity of the signature to any third party. However, the revocation of delegated rights has never been considered in the existing directed proxy signature schemes. In fact, in these directed proxy signature schemes, even if the period of delegation has expired, the proxy signer still can generate the valid proxy signature, and the original signer can do nothing to prevent it. Therefore, the authors give a solution to the delegation revocation problem and propose a directed proxy signature scheme with fast revocation in this study. The security and the invisibility of the authors’ scheme are proven based on the gap Diffie–Hellman assumption and under the decisional Diffie–Hellman problem in the standard model, respectively.

Compared with the visual-cryptography-based visual secret sharing, the random-grid-based visual secret sharing (RGVSS) has some technical advantages, such as no pixel expansion and no need of codebooks. Designed based on RGVSS, the user-friendly random-grid-based visual secret sharing (UFRGVSS) not only inherits the advantages of RGVSS but also overcomes the data management problem in RGVSS by taking meaningful images as shares. Unfortunately, up to now, the existing threshold UFRGVSS schemes are only (2, 2) ones, which should use two meaningful images with complementary colors as shares. What's more, there is no feasible method to construct UFRGVSS schemes for more general threshold access structures excluding (2, 2) threshold, let alone for general access structures (GASs). Motivated by these concerns, in this paper, by stamping the gray-scale images with the shares generated from the traditional RGVSS, a novel method was proposed to design the UFRGVSS scheme for GASs, in which the resulting shares can be any meaningful gray-scale images. Experimental results show the feasibility of the proposed method by assessing its performance under different situations. Literature retrieval shows that our work may be the first attempt to construct the UFRGVSS scheme for GASs. Copyright © 2015 John Wiley & Sons, Ltd.

A conventional matrix-based visual secret sharing scheme has the drawbacks of pixel expansion and the requirement of predetermined sophisticated codebooks. A random grid-based visual secret sharing (RGVSS) scheme is an effective approach to solving these two problems. However, up to now, most of the existing publications about the RGVSS scheme deal with the threshold access structures, while there is hardly any appropriate method to construct the RGVSS scheme for general access structures (GASs). In this paper, a novel method to construct a generalized RGVSS (GRGVSS) scheme for GASs is proposed. The construction algorithm consists of two parts. In the first part, a more general (n, n)-GRGVSS scheme is proposed; in addition, the visual quality of the reconstructed secret image for this GRGVSS scheme is formally analyzed. In the second part, we utilize this (n, n)-GRGVSS to construct the GRGVSS scheme for given GASs by treating the procedure as a nonlinear 0-1 programming model. In the experimental phase, by changing the given preconditions, we analyze the security of the proposed scheme and assess the visual quality of the recovered secret images for the proposed scheme under different situations. The simulation results show that the proposed GRGVSS scheme for GASs is feasible and efficient.

In earlier multi‐receiver signcryption schemes, in order to help the authorised receivers to find the corresponding information for decryption from the ciphertext, the list of identities of all authorised receivers should be included in the ciphertext as a necessary element. However, this method has directly led to the privacy leakage problem of receivers. Later, several anonymous multi‐receiver signcryption schemes use the Lagrange interpolation method to mix and hide the real identities of all receivers, so that the ciphertext does not expose identities of the receivers any longer. Therefore the Lagrange interpolation method is considered to be a perfect solution to the receiver anonymity problem, and multiple anonymous multi‐receiver signcryption schemes have been proposed based on it. However, recently, this method has been proven to be insecure because it cannot assure the anonymity of receivers either. In fact, in any of the existing anonymous schemes based on the Lagrange interpolation method, it is easy for one authorised receiver to judge whether anyone is an authorised receiver or not, which badly violates the receiver anonymity. Motivated by these concerns, the authors propose a new multi‐receiver signcryption scheme to solve this problem. Analyses show that the proposed scheme meets confidentiality, unforgeablity and the sender and receivers’ anonymity.

Fan et al . proposed an anonymous multi‐receiver identity‐based encryption scheme in 2010, and showed that the identity of any legal receiver can be kept anonymous to anyone else. In 2012, Wang et al . pointed out that Fan et al .’s scheme cannot achieve the anonymity and that every legal receiver can determine whether the other is one of the legal receivers. At the same time, they proposed an improved scheme based on Fan et al .’s scheme to solve this anonymity problem. Unfortunately, the authors find that Wang et al .’s improved scheme still suffers from the same anonymity problem. Any legal receiver of Wang et al .’s improved scheme can judge whether anyone else is a legal receiver or not. In this study, the authors shall give the detailed anonymity analysis of Wang et al .’s improved scheme.

Existing mobile authentication protocols are low in efficiency, because asymmetric encryption algorithms with large computational overheads are employed in these protocols to ensure user anonymity. In addition, the existing mobile authentication protocols have a long delay in fast reconnection, because these protocols may suffer from desynchronization attacks. In order to solve these problems, an efficient mutual authentication protocol with user anonymity for mobile networks is proposed. The proposed protocol ensures user anonymity by using one-way hash function. It reduces the delay time in fast reconnection, because once the session key between the mobile user and the foreign agent is found to be desynchronized in reconnection process, mobile users start the process of login and authentication from a new beginning immediately. The security of the proposed protocol is proved by using the provable security model. Compared with several existing authentication protocols for mobile networks, the proposed protocol is more secure and more effective.

As low-cost tags based on the EPC C-1 G-2 standard are much limited in storage capacity and computation power, most of the existing authentication protocols are too complicated to be suitable for these tags, and the design of authentication protocols conforming to the EPC C-1 G-2 standard is a big challenge. Recently, a mutual authentication protocol for RFID conforming to the EPC C-1 G-2 standard was proposed by Yeh et al., and it is claimed that this protocol has solved all security vulnerabilities in the existing RFID protocols. However, in fact, it is proven that this scheme is vulnerable to the tag tracing attack and suffers from the information leakage issue, and the complexity of the successful attack is only 216. To address these issues efficiently, a novel secure RFID authentication protocol conforming to the EPC C-1 G-2 standard is proposed. In the new scheme, the attack complexity is raised to 232 without changing the length of any protocol data. Analysis shows that our protocol can not only efficiently resist the tag information leakage and the tag tracing attack, but also have a significant advantage in performance over Yeh et al.'s protocol.

Multicasting is an important business in the field of the wireless local area network (WLAN), because the access point (AP) usually has to send the same message to each station (STA) of a specific group, and broadcasting the message to this group is one of the most efficient ways of communication. Chinese WLAN security standard, called WLAN Authentication and Privacy Infrastructure (WAPI), has taken secure multicasting into account, and proposed a Multicast Key Management Protocol (MKMP), in which the multicast session key (MSK) is distributed to each STA over the secure unicast channel built between STA and AP one by one. It is clear that the MSK distribution is very inefficient in performance, especially when the number of STAs is very large. In this study, a new MSK distribution protocol is proposed, and it can be used to substitute the original protocol in WAPI. Analyses show that the proposed protocol can achieve needed security requirements, and is more efficient than the original one in WAPI. Now, WAPI has been in the process of ISO/IEC standard building, and thus the authors think that their proposal can ameliorate WAPI largely and promote its ISO/IEC standard building.

Traditional minutiae matching algorithms assume that each minutia has the same discriminability. However, this assumption is challenged by at least two facts. One of them is that fingerprint minutiae tend to form clusters, and minutiae points that are spatially close tend to have similar directions with each other. When two different fingerprints have similar clusters, there may be many well matched minutiae. The other one is that false minutiae may be extracted due to low quality fingerprint images, which result in both high false acceptance rate and high false rejection rate. In this paper, we analyze the minutiae discriminability from the viewpoint of global spatial distribution and local quality. Firstly, we propose an effective approach to detect such cluster minutiae which of low discriminability, and reduce corresponding minutiae similarity. Secondly, we use minutiae and their neighbors to estimate minutia quality and incorporate it into minutiae similarity calculation. Experimental results over FVC2004 and FVC-onGoing demonstrate that the proposed approaches are effective to improve matching performance.

This letter develops a novel method for fingerprint singular point detection based on a new singularity representation of ridge-valley region called orientation entropy. The candidate singular point is obtained by the multiple-scale analysis of orientation entropy and some post processing steps are proposed to filter the spurious core and delta points. An iteration compensation scheme is proposed to search the precise location for core points against the offset further. Performance of the proposed method has been evaluated on the dataset of FVC2002 DB1. Experimental results show that the multiple-scale orientation entropy is correct and effective for singular detection and the location compensation scheme reduces the distance between the detection result and the truth singular point.

Sensor networks are composed of a large number of low power sensor devices. For secure communication among sensors, secret keys are required to be established between them. Considering the strict resource constraints of sensors, key infection has been proposed by Anderson, Chan, and Perrig. However, because the communication keys are broadcasted in plaintext in key infection, some of them may be eavesdropped by an adversary. To address this security issue, secrecy transfer is presented, which utilizes pre-loaded secret keying material to enhance the security performance of key infection. To thwart on-going cryptanalytic attacks, a key evolution scheme is proposed to continuously refresh shared keys. Key evolution forces the adversary to keep monitoring traffic all the time after compromising a key; even if the adversary has compromised a key, it cannot catch up with the key evolution process, and may lose control of the compromised key quickly in a noisy communication environment. Analysis results show that key infection, secrecy transfer, and key evolution present viable trade-offs between security and resource consumption for smart dust sensor networks.

Based on the hardness assumption of discrete logarithm problem and a group oriented encryption scheme, a new multi-party non-repudiation protocol is presented. The features of this protocol are the following: In the B2C or B2B e-commerce application,it is necessary for an organisations/people to deal with all kinds of requests, business documents, agreements, payments, contracts, acknowledgments as a batch.The protocol allows such organisations/people to send different messages to multiple different recipients, eliminates the previous restriction on the exchange of the same message. The protocol also utilizes an off-line third trusted party (TTP for short) and has higher efficiency than those protocols with an on-line TTP.

Since biometric data are unique and permanent characteristics of individuals, the privacy protection of biometric authentication schemes has become a common concern of the public. Recently, Tang et al. proposed a biometric-based authentication scheme in an attempt to solve the privacy concerns. However, their scheme cannot resist the attack of tamper. Motivated by these concerns, in this paper, we proposed a new biometric-based authentication scheme, which achieves identity privacy and transaction untraceability. Its security is based on the semantic security of the ElGamal algorithm. Analysis results show that our scheme is higher in efficiency than Tang et al. scheme does, and meanwhile, it can resist the tamper attack. It is concluded that the proposed scheme is more secure and more practical than the existing ones.

In literature [3], two new universal designated verifier signature proof schemes (UDVSP) based on hardness assumption of the discrete-logarithm problem were proposed at Asiacrypt '05. The UDVSP scheme were proven secure against impersonation attacks in random oracle under Type-1 attack and Type-2 attack. Unfortunately, these schemes are totally breakable by any attacker if the attacker is allowed to interact concurrently with many different prover “instances” as well as with the verifier (concurrent reset attacks for short). In this paper, the UDVSP schemes are shown insecure against impersonation under Type-1 attack and are also proven transferable, which contradicts the design goal of universal designated verifier signature scheme.

The tremendous evolution in networking, communication and mobility creates greater security assurance demand than can be provided by simple security measures, such as requiring passwords to gain access to a system. Biometric technologies are being used increasingly as an effective means. The combination of biometrics and cryptography is promising although there are some issues to be addressed. The key issue of the biometric encryption is how to deal with the contradiction about the veracity of cryptography and the simulation of biometric. The shielding function is a potential tool to solve this problem. In this paper, we shall review and analyze the classic biometrics-based cryptographic key management. And then, we construct a new fingerprint-based key binding scheme by using the shielding function and the WFMT method.

Trust management is an important issue in wireless sensor networks (WSNs). In this paper, we introduce the concept of trust and design a distributed event- triggered trust management model for WSNs. It combines cryptography, statistics, economics, data analysis and the other related fields. In this way, we can immediately identify and isolate the malice node, thereby creating a secure and reliable wireless sensor networks that can avoid some common attacks and ensure the security of the applications. And, we give the communication process and the computation model as well as how each trust management module works. So it is no longer a simple calculation model or a simple frame structure, and it has realistic feasibility and operability.

Wireless sensor networks are open architectures, so any potential threat can easily intercept, wiretap and counterfeit the information. Therefore, the safety of WSN is very important. Since any single key system cannot guarantee the security of the wireless sensor network for communications, this paper introduces a hierarchical key management scheme based on the different abilities of different sensor nodes in the clustered wireless sensor network. In this scheme, the nodes are distributed into several clusters, and a cluster head must be elected for each cluster. Private communication between cluster heads is realized through the encryption system based on the identity of each head while private communication between cluster nodes in a same cluster head is achieved through the random key preliminary distribution system. For cluster head node plays a pivotal role in this scheme, a trust management system should be introduced into the election of the cluster head which will exclude the malicious node from outside the cluster, thus improve the whole network security.

This short paper presents practical algorithms for mitigating inefficiency in reliability differentiation service based on geographical stateless routing, which has great potential applications in large scale wireless sensor networks (WSN). Based on available algorithm, the paper presents a mathematical formalization to systematic understanding the multipath redundancy problem of WSN. With the information beyond one hop and the load balancing mechanism, the data retransmission and reliability differentiation reassignments are reduced. The illustration and simulation demonstrate the proposed algorithmspsila effectiveness and the capability to provide reliability differentiation service.