With the advancing application of Unmanned Aerial Vehicles (UAVs, also known as Drones), UAV swarms are deployed in various complex mission scenarios to collaborate on particular assignments. However, UAV group communication encounters security and privacy challenges due to the open and insecure communication environment. Moreover, many existing UAV group authentication and key agreement (GAKA) schemes provide limited support for dynamic membership and fail to enforce mandatory participation of the leader UAV in hierarchical architectures. To address these limitations, we propose a blockchain-enabled scalable GAKA scheme tailored for dynamic IoD, named BSGAKA-IoD. The scheme achieves UAV threshold GAKA through an enhanced designated participant$ (ID, t, n)^*$-secret sharing scheme, which cryptographically enforces leader participation and enables threshold-based GAKA among the cluster leader and member UAVs. The scheme supports efficient group authentication, secure group key establishment, and dynamic joining/leaving without requiring any secure channel, while achieving$ O(n)$computational and communication complexity. We conduct comprehensive security analysis and develop two blockchain prototypes: a Solidity smart contract implementation validated in Remix, and a Hyperledger Fabric implementation benchmarked using Hyperledger Caliper under two network configurations. The results confirm that BSGAKA-IoD provides strong security guarantees, maintains linear scalability, and is feasible for deployment in realistic consortium-chain IoD settings.

Unmanned aerial vehicles (UAVs, also known as Drones) have been widely employed in military defense and civilian service. However, as UAVs communicate over insecure open wireless channels, the security challenges and privacy concerns are becoming increasingly prominent. Moreover, some existing schemes to achieve authentication and key agreement (AKA) among UAVs are spliced with the assistance of two UAV-2-GCS mechanisms, which are not flexible enough to be applied in the Internet of Drones (IoD) scenarios. This article proposes a blockchain-assisted AKA scheme for UAVs networks (BAKAS-UAV) referred to as BAKAS-UAV, which addresses security and privacy concerns and overcomes high computational and communication costs in the IoD. A blockchain-based network model is presented in which the ground station acts as an edge node and manages the blockchain, which assists AKA. Based on the network model, both types of AKA mechanisms, UAV-2-GCS and UAV-2-UAV, are proposed, respectively. In particular, the ground control station (GCS) does not participate in the AKA of UAV-2-UAV process; only upon the process is completed the two UAVs synchronize the updated information with GCS. We also implement a smart contract as the authentication service, and the experimental implementation demonstrates the availability of our scheme in IoD. Physical unclonable functions (PUFs) is introduced on the UAVs side to defend against physical capture attacks and also to implement AKA mechanisms. The semantic security is proved formally based on the real-or-random (ROR) model, and the informal analysis shows that the scheme satisfies the demanded security requirements. The scheme’s performance is evaluated by simulating the UAVs and GCS settings with Raspberry Pi 4B and MacOS platforms, respectively, with implementation of several cryptographic primitives. The experimental results show that BAKAS-UAV achieves high efficiency.

Quantum secret sharing plays a crucial role in quantum cryptography. The two main trends in quantum secret sharing are to address the problem of scheme failure due to participant spoofing and to improve the efficiency of quantum secret sharing. This paper focuses on the quantum secret sharing scheme with general access structure due to its flexibility. We design a special entangled state by resorting to Monotone Span Program (MSP). Based on the special 2-dimensional entangled state, an efficient and verifiable general quantum secret sharing (GQSS) scheme is proposed. In the GQSS scheme, the authorized participants only provide the X-basis measurement results of particles to recover and verify the shared secret, which makes that our scheme have lower communication consumption and quantum computational complexity. The analysis shows that the proposed scheme is simpler and more practical compared with related quantum secret sharing schemes.

Smart contracts are programmable units that possess the ability to execute a wide range of computational tasks, operating on a decentralized ledger called a blockchain, frequently employed for the management of valuable digital assets. Unlike conventional programs, once smart contracts are deployed, they are immutable and cannot be altered. As the value associated with smart contracts increases, they become increasingly enticing targets for potential attackers. It is therefore crucial to conduct comprehensive testing of smart contracts prior to their deployment. Fuzzing is an important testing approach. Regrettably, existing coverage-based fuzzing tools treat all covered code in the same manner and cannot perform extensive tests on specific code fragments. In this research, we present LDfuzz, a targeted greybox fuzzer explicitly developed for Ethereum smart contracts. Its primary goal is to generate inputs that efficiently navigate towards potentially suspicious program locations. We propose suspicious branch marked, an innovative approach that assesses branch-level security implications. Utilizing the suggested metrics as a foundation, we calculate the distance of each fuzzing inputs to the marked branch and formulate a power scheduling algorithm based on simulated annealing, which progressively allocates additional energy to seeds in proximity to the suspicious branch while diminishing energy for seeds that are more distant. We assess the efficacy of LDfuzz by conducting a comparative analysis with a leading fuzzer for smart contracts, benchmarking their respective performance. The results from our experimentation findings demonstrate that LDfuzz exhibits superior efficiency compared to current advanced tools in identifying bugs within real-world contracts. Moreover, LDfuzz excels beyond current tools in achieving broader branch coverage.

The widespread adoption of cloud computing and the exponential growth of data highlight the need for secure data sharing and querying. Attribute-based keyword search (ABKS) has emerged as an efficient means of searching encrypted data stored in the cloud. However, existing ABKS schemes incur high end-to-end delay and are vulnerable to quantum computer attacks and/or (insider) keyword guessing attacks (KGA). To address these vulnerabilities, this paper introduces a new concept called attribute-based authenticated encryption with keyword search (ABAEKS) and proposes an efficient ABAEKS scheme. Our ABAEKS has low end-to-end delay, and is resistant to both quantum computer attacks and (insider) KGA. In addition, we formalize the security model of ABAEKS system and prove its security in the random oracle model. Finally, we conduct a comprehensive performance evaluation of ABAEKS, and the experimental results show that our ABAEKS is computationally efficient and outperforms current state-of-the-art ABKS schemes.

Abstract Provable Data Possession (PDP) is of crucial importance in public cloud storage since it allows users to check the integrity of their outsourced data without downloading it. However, the existing PDP schemes, which are based on classical number-theoretic assumptions, are insecure under quantum attacks. In this paper, we propose the first PDP scheme from standard lattices, using a specific leveled fully homomorphic signature (FHS) scheme. To remove the complex key management of PDP cryptosystem on the public key infrastructure (PKI) setting, we employ a specific leveled identity-based (ID-based) FHS scheme to construct the first ID-based PDP scheme from standard lattices. Our two PDP schemes are secure under the standard small integer solution (SIS) assumption, which is conjectured to withstand quantum attacks. Furthermore, we conduct experimental evaluations to validate the feasibility of the proposed PDP schemes in practice.

Communication efficient secret sharing (CESS) schemes are a class of threshold schemes that aim to minimize the so-called decoding bandwidth, namely the necessary amount of communication between a combiner who wants to reconstruct the secret and the available participants storing shares of the secret. Previous works proved that the decoding bandwidth had a tight lower bound related to the number of available participants. Some threshold schemes that achieved the lower bound (optimal decoding bandwidth) and optimal information rate were constructed for a given number (non-universal case) or multiple distinct number ($\triangle $-universal case) of available participants. However, all those CESS schemes have large share sizes. Moreover, they have a common feature that each secret and share are a vector with multiple coordinates, which results in thedecoding delaysince the combiner must reconstruct a part of coordinates of the secret at first, and these recovered coordinates will be used to reconstruct another part of coordinates of the secret. In this work, we describe a new construction for CESS schemes of non-universal and$\triangle $-universal cases, whereas each secret and share of our schemes are asingleelement of a finite field$\mathbb {F}_{q^{e}}$, and each participant of an authorized subset provides asingleelement of a same subfield of$\mathbb {F}_{q^{e}}$to the combiner to reconstruct the secret. We find that the CESS schemes of this type, termed balanced CESS schemes, have an inevitable restriction on the number of available participants, but our schemes has no decoding delay. Furthermore, our schemes havesmallershare sizes than other existing works, which are realized by using a smaller sub-packetization$e$and a smaller base field$\mathbb {F}_{q}$. Indeed, the sub-packetizations of our schemes areminimumfor given$\mathbb {F}_{q}$among balanced CESS schemes. In addition, when our constructions are used to generate communication efficient$(n,r)$threshold schemes, we derive a generalized Shamir’s scheme that universally achieves optimal decoding bandwidth and optimal information rate forthe first time, where the restriction on the number of available participants is removed.

Fog-assisted mobile crowdsensing (FA-MCS) alleviates challenges with respect to computation, communication, and storage from the traditional model of mobile crowdsensing (MCS) “requester-server-users.” Data aggregation, as a specific MCS task, has attracted a lot of attentions in mining the potential value of the massive crowdsensing data. However, the process of data aggregation in FA-MCS may threaten the privacies of both users' data and aggregation results. The untrusted server and fog nodes (FNs) may damage the correctness of aggregation results. Moreover, bad FNs, which do not upload data to server or fail to verify successfully, can endanger the reliability of FA-MCS and the accuracy of aggregation results. To tackle these problems, we propose a verifiable, reliable, and privacy-preserving data aggregation scheme for FA-MCS. Specifically, the proposed scheme preserves privacies of both users' data and aggregation results, enables requester to verify the correctness of aggregation result, and is able to tolerate several bad FNs without affecting the data aggregation result. Through formal security analysis, the proposed scheme is shown to be secure and privacy preserving. Extensive experiments also show the proposed scheme is efficient and reliable.

Remote data backup technology facilitates data storage for users. However, an attacker may intercept some sensitive data on transfer. To solve this problem, sensitive data should be encrypted before uploading to the remote storage. Thus, protecting the secret encryption key is very important. Liu et al . have designed a scheme to protect the secret key using the secret‐sharing method and multi‐factor authentication. Unfortunately, the authors find some security weaknesses of Liu et al .’s scheme. Liu et al .’s scheme cannot resist offline password guessing attack, the server impersonation attack, the user impersonation attack and an attacker updating password/biometrics attack. They present an enhanced secure data backup scheme using multi‐factor authentication to overcome all above‐mentioned security threats. The user first divided a secret used to encrypt sensitive data into three shares using Shamir's secret sharing. Moreover, then the user uses the own password and biometrics to hide the true shares, and stores the pseudo three shares in the smart card, the laptop and the server, separately. Furthermore, the proposed scheme is illustrated in detail, and they give a security comparison of their scheme with Liu et al .’s scheme and computational costs.

ABSTRACT In 2003, Steinfeld et al. introduced the notion of universal designated verifier signature (UDVS), which allows a signature holder, who receives a signature from the signer, to convince a designated verifier whether he is possession of a signer's signature; at the same time, the verifier cannot transfer such conviction to anyone else. These signatures devote to protect the receiver's privacy, that is, the receiver may want to prove to any designated verifier who he is in possession of such signature signed by the known signer but reluctant to disclose it. Moreover, the receiver also does not want the verifier to be able to convince anyone that he is in possession of such signature. In the existing UDVS schemes, a secure channel is required between the signer and the signature holder to transfer the signature. This paper, for the first time, proposes the notion of universal designated verifier signcryption without this secure channel by combining the notions of UDVS and signcryption. We give the formal definitions and a concrete construction of universal designated verifier identity‐based signcryption scheme. We also give the formal security proofs for our scheme under the random oracle model. Copyright © 2013 John Wiley & Sons, Ltd.

In this paper, we analyze on the use of token-controlled public key encryption (TCE)schemes. We argue that for many of the applications in some possibilities of application in financial or legal scenarios, for example, the millionaire's will problem, the `private-opening' commitment, the scheduled payment problem, and the sealed-bid auctions and electronic lotteries problem, in the literature, the use of token-controlled public key encryption on its own, leads to inadequate solutions. We suggest that when considering applications of TCE, it is advisable to pay close attention to the lack of authentication and incorporate defences against the problems highlighted in this paper.

Jakobsson et al. first proposed the notions of designated verifier signature (DVS) and an enhanced version, strong designated verifier signature (SDVS) that only the designated verifier can verify the signature's validity. Since then, many improved schemes and variants have been proposed. In 2005, Lipmaa et al. introduced a delegation-attack and proposed a corresponding security concept, namely non-delegatability, which means that both the signer and the designated verifier can not delegate signing right to a third party to generate a valid signature. In this paper, we present a stronger security notion for the SDVS schemes, full non-delegatability, which not only needs the non-delegatability of signing, but also requires that non-delegatability of verifying. And we also analyze some previous SDVS schemes and find that all of them are not secure under the new security notion. At last, we propose an improved SDVS scheme based on identity (ID-SDVS). The proposed scheme is provably secure under the new security notion in the random oracle model.

Although the objective of secure communication can be achieved by using cryptographic tools, the undeniability that results from cryptographic properties may create a potential threat to the sender of the message. Unfortunately, most existing deniable protocols only provide 1-out-of-2 deniability. When both parties (the sender and the receiver) are allowed to deny generating the message, a dispute might occur between these two parties. The 1-out-of-2 deniable protocol can result in an unfair resolution of the dispute. Therefore, we propose a new model of deniability, called 1-out-of-∞ deniability, that can provide full deniability. The 1-out-of-∞ deniability protocol allows the originator of the message to deny that he or she generated the message, since there are an infinite number of possible message generators; at the same time, all transmitted messages can be protected and authenticated between the sender and the intended receiver. Our design can be implemented by using any public-key cryptography technique. We also analyze the correctness of the proposed protocols based on logical rules, and two practical examples are given to illustrate our design.

The first on-line/off-line signature scheme introduced by Even et al. in 1990 has two problems: (a) impractical signature length and (b) a one-time use of signature generated during the off-line phase. In 2001, Shamir and Tauman significantly shortened the length of the signature by using trapdoor hash families introduced by Krawczyk and Rabin in 2000. However, each trapdoor hash value and its signature in the off-line phase of Shamir and Tauman's signature scheme can be used for signing only one message in the on-line phase. In this paper, we propose multiple-collision trapdoor hash families based on discrete logarithm and factoring assumptions, and provide formal proofs of their security. We also introduce an efficient on-line/off-line signature scheme based on our proposed trapdoor hash families. Our on-line/off-line signature scheme can re-use a trapdoor hash value for signing multiple messages. If a signer includes this trapdoor hash value in the public-key digital certificate, there is no need to have any regular digital signature scheme to sign the trapdoor hash value in the off-line phase.

Key transfer protocols rely on a mutually trusted key generation center (KGC) to select session keys and transport session keys to all communication entities secretly. Most often, KGC encrypts session keys under another secret key shared with each entity during registration. In this paper, we propose an authenticated key transfer protocol based on secret sharing scheme that KGC can broadcast group key information to all group members at once and only authorized group members can recover the group key; but unauthorized users cannot recover the group key. The confidentiality of this transformation is information theoretically secure. We also provide authentication for transporting this group key. Goals and security threats of our proposed group key transfer protocol will be analyzed in detail.

Shamir proposed the first (t, n) threshold secret sharing scheme. Shamir's scheme is ideal and perfect. In this paper, we propose two modifications of Shamir's secret sharing scheme. In our first modification, each shareholder keeps both x-coordinate and y-coordinate of a polynomial as private share. In our second modification, dealer uses polynomial with degree larger than the threshold value t to generate shares for a (t, n) threshold scheme. We show that these two modified schemes are ideal and perfect. Using these two modifications, we design a multilevel threshold secret sharing schemes (MTSS). We prove that the proposed scheme is secure.