Span Programs Research Articles

Privacy enhanced secure compact attribute-based signature from MQ problem for monotone span program

The rapid advancement of computer networks has led to an increase in the exposure of messages within an open environment (cloud). Therefore, the confidentiality of the user's signing information is extremely essential to handle unauthorized access and alterations. Attribute-based signature (ABS) scheme is a significant primitive that ensures the privacy of the user's signing information. To endorse a message, the signer can generate a signature with his/her attributes that satisfy a policy without revealing any other information. Post-quantum attribute-based signature schemes are attractive construction options whose safety do not collapse in presence of quantum computers. This article presents the first attribute-based signature scheme in multivariate quadratic (MQ) setting. To generate the secret signing key, the salted-UOV technique is employed in our protocol. While signing, the well-known 3-pass identification protocol is coupled with the Fiat-Shamir transformation. More positively, our candidate relies on presenting the policy as a monotone span program. We also study existential unforgeability and the perfect privacy feature which ensures that a signature cannot be linked to any signing information. Moreover, our scheme is compact in the sense that it performs efficiently in terms of storage when contrasted to the existing post-quantum attribute-based signature schemes.

Improved Quantum Query Complexity on Easier Inputs

Quantum span program algorithms for function evaluation sometimes have reduced query complexity when promised that the input has a certain structure. We design a modified span program algorithm to show these improvements persist even without a promise ahead of time, and we extend this approach to the more general problem of state conversion. As an application, we prove exponential and superpolynomial quantum advantages in average query complexity for several search problems, generalizing Montanaro's Search with Advice [Montanaro, TQC 2010].

A privacy preserving quantum aggregating technique with simulation

Quantum aggregation is a basic operation of secure multiparty quantum computation. All the existing techniques are based on the (n,n) threshold, where n is the total number of players. If any of them is corrupted then these techniques cannot execute correctly. However, the proposed technique is based on the (t,n) threshold. If the players are honest then this technique can perform the aggregation. This technique is based on the monotone span program, access structure, linear secret sharing, control-NOT gate, quantum Fourier transform, blind matrix, and Pauli operator. The proposed technique can aggregate the secrets securely and efficiently. We also simulate the proposed technique using IBM quantum computer to verify the correctness and feasibility.

Quantum multi-secret sharing scheme with access structures and cheat identification

This work proposes a [Formula: see text]-dimensional quantum multi-secret sharing scheme with a cheat-detection mechanism. The dealer creates multiple secrets and distributes the shares of these secrets using multi-access structures and a monotone span program. The dealer detects the cheating of each participant using the black box’s cheat-detection mechanism. To detect the participants’ deceit, the dealer distributes secret shares’ shadows derived from a randomly invertible matrix [Formula: see text] to the participants, stored in the black box. The black box identifies the participant’s deceitful behavior during the secret recovery phase. Only honest participants authenticated by the black box acquire their secret shares to recover the multiple secrets. After the black box cheating verification, the participants reconstruct the secrets by utilizing the unitary operations and quantum Fourier transform. The proposed protocol is reliable in preventing attacks from eavesdroppers and participants. The scheme’s efficiency is demonstrated in different noise environments: dit-flip noise, [Formula: see text]-phase-flip noise and amplitude-damping noise, indicating its robustness in practical scenarios. The proposed protocol provides greater versatility, security and practicality.

Shorter ZK-SNARKs from square span programs over ideal lattices

Zero-knowledge succinct non-interactive arguments of knowledge (zk-SNARKs) are cryptographic protocols that offer efficient and privacy-preserving means of verifying NP language relations and have drawn considerable attention for their appealing applications, e.g., verifiable computation and anonymous payment protocol. Compared with the pre-quantum case, the practicability of this primitive in the post-quantum setting is still unsatisfactory, especially for the space complexity. To tackle this issue, this work seeks to enhance the efficiency and compactness of lattice-based zk-SNARKs, including proof length and common reference string (CRS) length. In this paper, we develop the framework of square span program-based SNARKs and design new zk-SNARKs over cyclotomic rings. Compared with previous works, our construction is without parallel repetition and achieves shorter proof and CRS lengths than previous lattice-based zk-SNARK schemes. Particularly, the proof length of our scheme is around 23.3%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$23.3\\%$$\\end{document} smaller than the recent shortest lattice-based zk-SNARKs by Ishai et al. (in: Proceedings of the 2021 ACM SIGSAC conference on computer and communications security, pp 212–234, 2021), and the CRS length is 3.6×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$3.6\ imes$$\\end{document} smaller. Our constructions follow the framework of Gennaro et al. (in: Proceedings of the 2018 ACM SIGSAC conference on computer and communications security, pp 556–573, 2018), and adapt it to the ring setting by slightly modifying the knowledge assumptions. We develop concretely small constructions by using module-switching and key-switching procedures in a novel way.

Inner-Product Matchmaking Encryption: Bilateral Access Control and Beyond Equality

We present an inner-product matchmaking encryption (IP-ME) scheme achieving weak privacy and authenticity in prime-order groups under symmetric external Diffie–Hellman (SXDH) assumption in the standard model. We further present an IP-ME with Monotone Span Program Authenticity (IP-ME with MSP Auth) scheme, where the chosen sender policy is upgraded to MSP, and the scheme also achieves weak privacy and authenticity in prime-order groups under SXDH assumption in the standard model. Both of the schemes have more expressive functionalities than identity-based matchmaking encryption (IB-ME) scheme, and are simpler than Ateniese et al.’s modular ME scheme (Crypto’ 19). But our schemes only achieve a very limited flavor of security, which is reflected in the privacy.

Authenticable quantum multi-secret sharing scheme based on monotone span program

Authenticable quantum multi-secret sharing scheme based on monotone span program

Code-routing: a new attack on position verification

The cryptographic task of position verification attempts to verify one party's location in spacetime by exploiting constraints on quantum information and relativistic causality. A popular verification scheme known as f-routing involves requiring the prover to redirect a quantum system based on the value of a Boolean function f. Cheating strategies for the f-routing scheme require the prover use pre-shared entanglement, and security of the scheme rests on assumptions about how much entanglement a prover can manipulate. Here, we give a new cheating strategy in which the quantum system is encoded into a secret-sharing scheme, and the authorization structure of the secret-sharing scheme is exploited to direct the system appropriately. This strategy completes the f-routing task using O(SPp(f)) EPR pairs, where SPp(f) is the minimal size of a span program over the field Zp computing f. This shows we can efficiently attack f-routing schemes whenever f is in the complexity class ModpL, after allowing for local pre-processing. The best earlier construction achieved the class L, which is believed to be strictly inside of ModpL. We also show that the size of a quantum secret sharing scheme with indicator function fI upper bounds entanglement cost of f-routing on the function fI.

Efficient quantum secret sharing scheme based on monotone span program

How to efficiently share secrets among multiple participants is a very important problem in key management. In this paper, we propose a multi-secret sharing scheme based on the Greenberger Horne Zeilinger (GHZ) state. First, the distributor uses monotone span program to encode the secrets and generate the corresponding secret shares to send to the participants. Then, each participant uses the generalized Pauli operator to embed its own secret share into the transmitted particle. The participant who wants to get the secrets can get multiple secrets at the same time by performing a GHZ-state joint measurement. Furthermore, since this scheme is based on a monotone span program, its access structure is more general than the access structure (t, n) threshold. Compared with other schemes, our proposed scheme is more efficient, less computational cost.

Bounded-collusion decentralized ABE with sublinear parameters

In this paper, we propose a decentralized ABE scheme against bounded collusion which means the number of users in the system is a-prior bounded. The scheme enjoys public key and ciphertext of sublinear sizes in the number of users in the system while all prior constructions require linear sizes. Besides, our scheme achieves semi-adaptive security under bilateral k-Lin assumption and SXDH assumption in a pairing group. Keep the same as the previous constructions, the scheme supports monotone span program as a policy and does not rely on the random oracle.Technically, we follow Wang et al.'s “linear secret sharing scheme (LSSS) + inner-product functional encryption (IPFE)” paradigm [PKC'19] and use (an extended variant of) functional encryption for quadratic functions (QFE) in the place of IPFE. By this, we encrypt with sublinear-size random coins and later expand them to linear-size entropy for security proof. Roughly, the use of QFE requires bilateral k-Lin assumption while the entropy expansion relies on SXDH.

Efficient Revocable Storage Attribute-based Encryption With Arithmetic Span Programs in Cloud-Assisted Internet of Things

Revocable storage and efficient description of the access policy are necessary to enhance the practicality of the attribute-based encryption (ABE) in real-life scenarios, such as cloud-assisted Internet of Things (IoT). Nevertheless, existing ABE works fail to balance the two vital factors. In this paper, we construct an efficient revocable storage ciphertext-policy attribute-based encryption with arithmetic span programs (RS- CPABE-ASP). The arithmetic span program (ASP) is elegantly utilized as the access structure to reduce the unnecessary cost for defining access policy. Combining the indirect revocation and the ciphertext update mechanism, our work prevents the revoked user unable to access the newly generated data and the old data that can be accessed before. As shown in the outsourced version of RS-CPABE-ASP, the costly part for users to decrypt the data can be outsourced to powerful cloud servers. In this way, users in our RS-CPABE-ASP are able to access their data in a more efficient way by merely one exponential operation. Finally, we carry out detailed theoretical analysis and experimental simulations to evaluate the performance of our work. The results fairly show that our proposed work is efficient and feasible in cloud-assisted IoT.

Краткие неинтерактивные аргументы с нулевым разглашением на основе наборов полиномов

The paper discusses the basic principles of construction and the main types of zeroknowledge succinct non-interactive argument of knowledge (zk-SNARK) which is used in the model of a three-way insecure computing environment and based on sets of polynomials. A number of zk-SNARK cryptographic protocols with different algorithms for generating public parameters (Trusted Setup) are given, constructing succinct proofs of reliability calculations (Prover) and public/designated verification of proofs (Verifier). The cases of satisfying the feasibility of discrete functions (arithmetic/ Boolean circuits) using different polynomial sets are presented in quadratic arithmetic programs (QAP), square arithmetic programs (SAP), quadratic span programs (QSP), square span programs (SSP), quadratic polynomial programs (QPP), etc., also the use of authenticated data are described. The cryptographic transformations needed to build zk-SNARKs based on symmetric and asymmetric hash functions, exponential knowledge problems, digital signatures, homomorphic encryption, bilinear pairings based on elliptic curves, etc. are presented. Examples of multilateral verifiable calculations based on zk-SNARK are given.

An Efficient Integrity Checking Scheme with Full Identity Anonymity for Cloud Data Sharing

Cloud storage services can support data sharing for a group of users. However, the cloud server may lose some of the shared data when attacked. The integrity of stored data is a key issue for cloud storage. However, identity anonymity, an important problem in data integrity, has not been fully investigated yet. Furthermore, the existing schemes of data integrity checking are usually based on public key infrastructure and thus have to perform complex certificate management. In this paper, we propose an efficient integrity checking scheme to achieve full identity anonymity. Additionally, the proposed scheme can reduce the workloads of certificate management and simplify key management. Inspired by the idea of attribute-based signature, we devise a common predicate to manage the identities of legitimate users and disable illegal users from joining the data sharing. By adopting the technique of the monotone span program, the legitimate user can compute the valid authenticators of shared data for all attributes in the common predicate without the need of binding his attribute set to the shared data. Whereupon, the user's identity remains anonymous to all parties in the data sharing because he can share the data and authenticators without revealing his attribute set to other parties. The extensive experimental results demonstrate that the proposed scheme has less computational and communication overhead compared with the existing schemes while achieving full identity anonymity.

Stem Cell- and Cell-Based Therapies for Ischemic Stroke.

Stroke is the second cause of disability worldwide as it is expected to increase its incidence and prevalence. Despite efforts to increase the number of patients eligible for recanalization therapies, a significant proportion of stroke survivors remain permanently disabled. This outcome boosted the search for efficient neurorestorative methods. Stem cells act through multiple pathways: cell replacement, the secretion of growth factors, promoting endogenous reparative pathways, angiogenesis, and the modulation of neuroinflammation. Although neural stem cells are difficult to obtain, pose a series of ethical issues, and require intracerebral delivery, mesenchymal stem cells are less immunogenic, are easy to obtain, and can be transplanted via intravenous, intra-arterial, or intranasal routes. Extracellular vesicles and exosomes have similar actions and are easier to obtain, also allowing for engineering to deliver specific molecules or RNAs and to promote the desired effects. Appropriate timing, dosing, and delivery protocols must be established, and the possibility of tumorigenesis must be settled. Nonetheless, stem cell- and cell-based therapies for stroke have already entered clinical trials. Although safe, the evidence for efficacy is less impressive so far. Hopefully, the STEP guidelines and the SPAN program will improve the success rate. As such, stem cell- and cell-based therapy for ischemic stroke holds great promise.

State and Local Chronic Disease Programs Adapt and Pivot to Address Community Needs During the COVID-19 Pandemic: Examples From CDC Funded SPAN, REACH, and HOP Programs.

State and Local Chronic Disease Programs Adapt and Pivot to Address Community Needs During the COVID-19 Pandemic: Examples From CDC Funded SPAN, REACH, and HOP Programs.

Time- and Query-optimal Quantum Algorithms Based on Decision Trees

It has recently been shown that starting with a classical query algorithm (decision tree) and a guessing algorithm that tries to predict the query answers, we can design a quantum algorithm with query complexity O( √ GT where T is the query complexity of the classical algorithm (depth of the decision tree) and G is the maximum number of wrong answers by the guessing algorithm [ 3 , 14 ]. In this article, we show that, given some constraints on the classical algorithms, this quantum algorithm can be implemented in time Õ (√ GT ). Our algorithm is based on non-binary span programs and their efficient implementation. We conclude that various graph-theoretic problems including bipartiteness, cycle detection, and topological sort can be solved in time O(n 3/2 log 2 n ) and with O(n 3/2 ) quantum queries. Moreover, finding a maximal matching can be solved with O(n 3/2 ) quantum queries in time O(n 3/2 log 2 n ), and maximum bipartite matching can be solved in time O(n 2 log 2 n ).

Research on Access Control Scheme of System Wide Information Management Based on Attribute Association

System wide information management (SWIM) involves civil aviation system control, intelligence, alarm, traffic, and other data. These data are transmitted in various forms, making SWIM system vulnerable to sensitive information leakage, data tampering, denial, and other security threats. In this article, an attribute-based air traffic management (ATM) information access control scheme is proposed to solve the security threat of SWIM. An improved extensible access control markup language (XACML) authorization model is established, combining linear secret sharing scheme (LSSS) matrix structure and monotone span program (MSP); an attribute association algorithm is designed to establish the attribute association relationship between services and users. Experimental results show that the attribute association algorithm improves the time complexity, but the algorithm can support richer policy representation capability, and the proposed ATM information access control scheme is more efficient and can effectively reduce the space cost. This scheme can achieve more fine-grained and flexible access control.

Unbounded and Efficient Revocable Attribute-Based Encryption With Adaptive Security for Cloud-Assisted Internet of Things

Existing attribute-based encryption (ABE) schemes with revocation to secure the cloud-assisted Internet of Things (IoTs) raise challenges, such as eliminating the need for predefined public parameters in system initialization, performing the encryption and decryption operations efficiently, and achieving adaptive security under standard security assumption. In this article, we address these challenges by proposing an unbounded and efficient revocable ABE scheme with adaptive security for cloud-assisted IoTs. Distinct from the previous approaches in this field, our scheme not only efficiently realizes access control over encrypted data in a fine-grained and revocable way but also is proved to be adaptively secure under standard decision linear assumption. Meanwhile, the parameters do not need to be predefined in the system initialization and thus, our scheme satisfies the unbounded property. Moreover, the monotonic span program (MSP) is elegantly utilized as the access structure to reduce the number of bilinear pairing and exponentiation operations for encryption and decryption. Theoretical performance analysis and experiment evaluation disclose that our proposed scheme owns outstanding feasibility, efficiency, and effectiveness.

Efficient Attribute-Based Signatures for Unbounded Arithmetic Branching Programs

This paper presents the first attribute-based signature (ABS) scheme in which the correspondence between signers and signatures is captured in an arithmetic model of computation. Specifically, we design a fully secure, i.e., adaptively unforgeable and perfectly signer-private ABS scheme for signing policies realizable by arithmetic branching programs (ABP), which are a quite expressive model of arithmetic computations. On a more positive note, the proposed scheme places no bound on the size and input length of the supported signing policy ABP’s, and at the same time, supports the use of an input attribute for an arbitrary number of times inside a signing policy ABP, i.e., the so called unbounded multi-use of attributes. The size of our public parameters is constant with respect to the sizes of the signing attribute vectors and signing policies available in the system. The construction is built in (asymmetric) bilinear groups of prime order, and its unforgeability is derived in the standard model under (asymmetric version of) the well-studied decisional linear (DLIN) assumption coupled with the existence of standard collision resistant hash functions. Due to the use of the arithmetic model as opposed to the boolean one, our ABS scheme not only excels significantly over the existing state-of-the-art constructions in terms of concrete efficiency, but also achieves improved applicability in various practical scenarios. Our principal technical contributions are (a) extending and refining the techniques of Okamoto and Takashima [PKC 2011, PKC 2013], which were originally developed in the context of boolean span programs, to the arithmetic setting; and (b) innovating new ideas to allow unbounded multi-use of attributes inside ABP’s, which themselves are of unbounded size and input length.

A Fully Secure KP-ABE Scheme on Prime-Order Bilinear Groups through Selective Techniques

Key-policy attribute-based encryption (KP-ABE) is the cryptographic primitive which enables fine grained access control while still providing end-to-end encryption. Although traditional encryption schemes can provide end-to-end encryption, users have to either share the same decryption keys or the data have to be stored in multiple instances which are encrypted with different keys. Both of these options are undesirable. However, KP-ABE can provide less key overhead compared to the traditional encryption schemes. While there are a lot of KP-ABE schemes, none of them simultaneously supports multiuse of attributes, adaptive security, monotone span programs, and static security assumption. Hence, we propose a fully secure KP-ABE scheme for monotone span programs in prime-order group. This scheme uses selective security proof techniques to obtain the requisite ingredients for full security proof. This strengthens the correlation between selective and full security models and enables the transition of the best qualities in selective security models to fully secure systems. The security proof is based on decisional linear assumption and three-party Diffie–Hellman assumption.