Collusion Resistance Research Articles

A Verifiable and Traceable Asymmetric Fingerprinting Scheme for Encrypted 3D Models of Oblique Photography

ABSTRACTVerifiability and traceability are significant challenges in the safe use of 3D models of oblique photography. Although existing methods can achieve data verifiability, they suffer from issues such as wrongful accusations of legitimate users, difficulties in tracing unauthorized users, and data leakage during transmission. To address these issues, we propose a verifiable and traceable asymmetric fingerprinting scheme for encrypted 3D models of oblique photography. First, the fingerprint to be embedded is generated interactively by both parties involved in the transaction. The publisher cannot obtain the actual information of the fingerprint, as it is known solely by the user. This effectively ensures the asymmetry of the fingerprint. Next, a fingerprint mapping mechanism is established based on the maximum angle of the triangular facets, embedding the fingerprint information losslessly by adjusting the storage order of the triangle vertices. Finally, the vertex coordinates of the model are converted to positive integers, and the model containing the fingerprint is asymmetrically encrypted using the CRT‐Paillier method to enable secure data transmission. Experimental results demonstrate that the proposed scheme does not cause a loss of precision to the model and exhibits strong robustness and collusion resistance against common attacks. Additionally, this scheme can effectively prevent false accusations against legitimate users and accurately trace illegal users.

Aggregate Attribute-Based Signature Scheme for Scalable and Efficient Cryptographic Systems

Attribute-Based Signatures (ABS) provide a cryptographic mechanism enabling signers to authenticate messages while preserving their privacy, based on a set of attributes. This paper introduces an Aggregate Attribute-Based Signature (AABS) scheme that leverages bilinear pairings to support efficient aggregation of multiple signatures into a compact form. The proposed scheme is designed to address scalability challenges in systems requiring numerous signatures, such as healthcare data sharing, vehicular networks, and blockchain-based applications. The scheme ensures essential security properties, including unforgeability, anonymity, and collusion resistance, under the Bilinear Diffie-Hellman (BDH) assumption. Each signer generates a signature based on their attributes, which can then be aggregated into a single signature for a given message by an authorized entity. Verification is efficient, requiring only a constant number of pairing operations, regardless of the number of signers or attributes involved. A rigorous security analysis demonstrates that the scheme resists forgery attempts and unauthorized collusion, ensuring reliable message authentication even in adversarial settings. Furthermore, the compactness of the aggregated signatures reduces storage and computational overhead, making it ideal for resource-constrained environments. This work paves the way for more scalable, privacy-preserving, and efficient attribute-based cryptographic solutions.

A variable threshold ring signature scheme for privacy protection in smart city blockchain applications

In smart city deployments, blockchain offers decentralized control over services and data, yet it also introduces stringent privacy and scalability challenges. Ring signatures can authenticate transactions while preserving signer anonymity, but existing schemes seldom provide both unconditional strong anonymity and robust collusion resistance, and they often incur burdensome key management and costly verification. To overcome these limitations, we present a distributed, attribute-based ring signature scheme with a flexible threshold policy. Our approach leverages (n, t)-threshold distributed key-generation protocol to eliminate any single point of trust and to simplify key distribution. By encoding user identity attributes directly into signature keys, the construction guarantees provable unforgeability, unconditional anonymity, and resistance to collusion among malicious users. We further introduce an optimized batch-verification algorithm that cuts the number of expensive pairing checks per signature from O(n) to O(1)+n, dramatically improving throughput. Security proofs in the random-oracle model and detailed performance evaluations confirm that our scheme is both practical and scalable for privacy-critical blockchain applications in smart cities.

CRT and PUF-Based Self/Mutual-Healing Key Distribution Protocol With Collusion Resistance and Revocation Capability

CRT and PUF-Based Self/Mutual-Healing Key Distribution Protocol With Collusion Resistance and Revocation Capability

Three-factor authentication and key agreement protocol with collusion resistance in VANETs

Three-factor authentication and key agreement protocol with collusion resistance in VANETs

Attribute‐Based Access Control With Credible Outsourcing and Collusion‐Resistant Revocation Based on Blockchain for Iomt

ABSTRACTThe maturity of cloud computing and the Internet of Things (IoT) has greatly facilitated the growth of the healthcare industry. Nowadays, Personal Health Records (PHRs) collected by the Internet of Medical Things (IoMT) are shared with healthcare institutions through the public cloud. Ciphertext‐Policy Attribute‐Based Encryption (CP‐ABE) can protect PHRs' confidentiality while promoting sharing efficiency. However, current schemes suffer from high computation overhead and data leakage caused by privilege revocation. This paper proposes a CP‐ABE scheme with credible outsourcing and collusion‐resistant revocation based on blockchain for IoMT. Most encryption and decryption operations are outsourced to the cloud server, and the outsourced computation correctness is verified by the blockchain credibly. The user needs to perform only two exponential operations in encryption and one exponential operation in decryption. Furthermore, we no longer use the cloud server to update the ciphertext in privilege revocation to avoid data leakage. Meanwhile, we add a ciphertext private key bound to the ciphertext to perform decryption together with the attribute private key. Only users whose attributes satisfy the policy can obtain , and the smart contract credibly verifies this process. The revoked user cannot decrypt the ciphertext due to the lack of . We performed a rigorous security analysis of our scheme, encompassing confidentiality, collusion resistance, revocability, and blockchain, which collectively validate the robustness and security of our approach. What is more, we benchmarked our scheme against state‐of‐the‐art approaches in terms of storage, communication, and computation. The results demonstrate that our scheme maintains competitive performance across all metrics.

Performance analysis of the proxy-based and collusion-resistant revocable CPABE framework

An efficient revocation of access rights in ciphertext policy attribute-based encryption (CPABE) schemes has multiple challenges, particularly for lightweight devices. Thus, extensive research on the existing studies enforcing and governing access control has been conducted. The methodologies used in the existing CPABE (bilinear pairing cryptography based) schemes to revoke users at the system and attribute levels have been focused on in the current study. The existing studies have been examined on the basis of the following parameters for revocation: type of revocation addressed, level of collusion resistance, dynamicity achieved, scalability of revocation, and computational cost incurred. It has been observed in the study that no single scheme achieves all the revocation properties and addresses both types of revocation. The module proposed in proxy-based and collusion-resistant multi-authority revocable CPABE (PCMR-CPABE) efficiently addresses both types of revocation and is fully collusion-resistant, dynamic, and scalable. The present paper extends the study on PCMR-CPABE and presents a performance analysis of the module in terms of functional specifications and computational cost. The presented analysis has compared the performance of the existing cutting-edge schemes with the PCMR-CPABE module and has proved that the proposed module is better in terms of functionality and is computationally inexpensive.

A secure cross-domain authentication scheme based on threshold signature for MEC

The widespread adoption of fifth-generation mobile networks has spurred the rapid advancement of mobile edge computing (MEC). By decentralizing computing and storage resources to the network edge, MEC significantly enhances real-time data access services and enables efficient processing of large-scale dynamic data on resource-limited devices. However, MEC faces considerable security challenges, particularly in cross-domain service environments, where every device poses a potential security threat. To address this issue, this paper proposes a secure cross-domain authentication scheme based on a threshold signature tailored to MEC’s multi-subdomain nature. The proposed scheme employs a (t,n) threshold mechanism to bolster system resilience and security, catering to large-scale, dynamic, and decentralized MEC scenarios. Additionally, the proposed scheme features an efficient authorization update function that facilitates the revocation of malicious nodes. Security analysis confirmed that the proposed scheme satisfies unforgeability, collusion resistance, non-repudiation and forward security. Theoretical evaluation and experimental simulation verify the effectiveness and feasibility of the proposed scheme. Compared with existing schemes, the proposed scheme has higher computational performance while implementing secure authorization updates.

Securing Internet of Things Applications Using Software-Defined Network-Aided Group Key Management with a Modified One-Way Function Tree

Group management is practiced to deploy access control and to ease multicast and broadcast communication. However, the devices that constitute the Internet of Things (IoT) are resource-constrained, and the network of IoT is heterogeneous with variable topologies interconnected. Hence, to tackle heterogeneity, SDN-aided centralized group management as a service framework is proposed to provide a global network perspective and administration. Group management as a service includes a group key management function, which can be either centralized or decentralized. Decentralized approaches use complex cryptographic primitives, making centralized techniques the optimal option for the IoT ecosystem. It is also necessary to use a safe, scalable approach that addresses dynamic membership changes with minimal overhead to provide a centralized group key management service. A group key management strategy called a one-way Function Tree (OFT) was put forth to lower communication costs in sizable dynamic groups. The technique, however, is vulnerable to collusion attacks in which an appending and withdrawing device colludes and conspires to obtain unauthorized keys for an unauthorized timeline. Several collusion-deprived improvements to the OFT method are suggested; however, they come at an increased cost for both communication and computation. The Modified One-Way Function Tree (MOFT), a novel technique, is suggested in this proposed work. The collusion resistance of the proposed MOFT system was demonstrated via security analysis. According to performance studies, MOFT lowers communication costs when compared to the original OFT scheme. In comparison to the OFT’s collusion-deprived upgrades, the computation cost is smaller.

Secure Proxy Re-Encryption Protocol for FANETs Resistant to Chosen-Ciphertext Attacks

In emergency situations, ensuring the secure transmission of medical information is critical. While existing schemes address on-road emergencies, off-road scenarios present unique challenges due to hazardous locations inaccessible to conventional vehicles. This research introduces a protocol for off-road emergencies, leveraging flying ad hoc networks (FANETs) formed by drones. The protocol, designed for users receiving emergency treatment, employs cryptographic techniques to protect sensitive information. To overcome the challenge of decrypting user medical records at emergency centers without the healthcare provider’s key, proxy re-encryption is employed. The control center (CC) securely generates encryption and decryption keys, facilitating the re-encryption process by the cloud server (CS) and transmission to the emergency center (E). The proposed protocol, free from pairing functions, underwent security and efficiency analyses, demonstrating resilience against chosen-ciphertext attacks (CCA) and collusion resistance (CR). Execution times of approximately 0.02 and 0.0 s for re-encryption and decryption processes, respectively, for a message size of 2000 bytes highlighted the efficiency of the protocol. The research contributes a secure and efficient proxy re-encryption protocol for off-road emergency medical information transmission within FANETs.

E-DPNCT: an enhanced attack resilient differential privacy model for smart grids using split noise cancellation

High frequency reporting of energy consumption data in smart grids can be used to infer sensitive information regarding the consumer’s life style and poses serious security and privacy threats. Differential privacy (DP) based privacy models for smart grids ensure privacy when analysing energy consumption data for billing and load monitoring. However, DP models for smart grids are vulnerable to collusion attack where an adversary colludes with malicious smart meters and un-trusted aggregator in order to get private information from other smart meters. We first show the vulnerability of DP based privacy model for smart grids against collusion attacks to establish the need of a collusion resistant privacy model. Then, we propose an Enhanced Differential Private Noise Cancellation Model for Load Monitoring and Billing for Smart Meters (E-DPNCT) which not only provides resistance against collusion attacks but also protects the privacy of the smart grid data while providing accurate billing and load monitoring. We use differential privacy with a split noise cancellation protocol with multiple master smart meters (MSMs) to achieve collusion resistance. We propose an Enhanced Differential Private Noise Cancellation Model for Load Monitoring and Billing for Smart Meters (E-DPNCT) to protect the privacy of the smart grid data using a split noise cancellation protocol with multiple master smart meters (MSMs) to provide accurate billing and load monitoring and resistance against collusion attacks. We did extensive comparison of our E-DPNCT model with state of the art attack resistant privacy preserving models such as EPIC for collusion attack. We simulate our E-DPNCT model with real time data which shows significant improvement in privacy attack scenarios. Further, we analyze the impact of selecting different sensitivity parameters for calibrating DP noise over the privacy of customer electricity profile and accuracy of electricity data aggregation such as load monitoring and billing.

Formula omitted]ODNS: A distributed approach to DNS anonymization with collusion resistance

The traditional Domain Name System (DNS) lacks fundamental security and privacy features in its design. As privacy concerns increased on the Internet, security and privacy enhancements of DNS have been actively investigated. Specifically, in the context of user privacy in DNS queries, several relay-based anonymization schemes have been recently introduced. However, these schemes are vulnerable to collusion between relays and full-service resolvers, which means user identities cannot be hidden from resolvers. This paper introduces a new concept for achieving user anonymity in DNS queries through a multiple-relay-based approach, called μODNS (Mutualized Oblivious DNS), by extending the concept of existing relay-based schemes. μODNS introduces a reasonable assumption that each user has at least one trusted or dedicated relay within the network and mutually shares the relay with other users. The user simply sets his trusted relay as the next-hop relay to convey his queries to the resolver and randomly chooses its zero or more subsequent relays shared by other entities. Under this assumption, the user’s identity remains concealed from the target resolver in μODNS even if an unknown subset of relays colludes with the resolver. Namely, in μODNS, users can preserve their anonymity by paying a small cost of sharing their resources. Additionally, we extend existing protocols, Anonymized DNSCrypt and Oblivious DoH, to provide practical Proof-of-Concept specifications and implementations as instances of μODNS. These implementations are publicly available on the Internet as open-source software and public services. Furthermore, we demonstrate, through measurements of round-trip times for DNS messages, that our implementation can minimize the performance degradation resulting from its privacy enhancements, achieving performance levels that maintain the positive user experiences observed in existing schemes.

One for all: Efficient verifiable dynamic multi-user searchable encryption in the presence of corrupted users

One for all: Efficient verifiable dynamic multi-user searchable encryption in the presence of corrupted users

A cloud based enhanced CPABE framework for efficient user and attribute-level revocation

Outsourcing massive amounts of data to the cloud service provider (CSP) has raised various security concerns for data confidentiality and access control. The ciphertext policy attribute based encryption (CPABE) scheme allows data owners to impose access control on their cloud-resident sensitive data. This paper has studied the approaches adopted to revoke users by the existing bilinear pairing cryptography based CPABE schemes. The existing studies have suggested solutions to revocation either by updating the non-revoked users’ keys or updating the ciphertext. Such approaches increase computational overhead for resource-constrained devices. In addition, a few studies have discussed the possibility of the CSP becoming dishonest and colluding with the revoked users. The likelihood of a collusion attack caused by the CSP and the revoked users also needs extensive attention. The development of the proposed proxy-based framework aims to extend the existing CPABE scheme and simplify the revocation of access rights at the user and attribute level with scalability, dynamicity, collusion resistance, and forward/backward secrecy. The proposed framework uses bilinear pairing cryptography and LSSS as an access structure. Furthermore, the security and performance analysis of the proposed framework reflects that it is implementable, better, and more secure than the existing work.

Nereus: Anonymous and Secure Ride-Hailing Service Based on Private Smart Contracts

Security and privacy issues have become a major hindrance to the broad adoption of Ride-Hailing Services (RHSs). In this paper, we introduce a new collusion attack initiated by the Ride-Hailing Service Provider (RHSP) and a driver that could easily link the real riders and their anonymous requests (credentials). Besides this attack, existing work requires heavy computations to execute user matching, and it is challenging for riders to verify matching results. Meanwhile, a malicious driver may cancel an assigned ride order due to its short distance. To address these issues, we present a RHS system named Nereus to support collusion resistance, efficiency, verifiability, and accountability. First, we integrate a smart contract into a Software Guard Extensions (SGX) enclave to establish a <i>private smart contract</i> for collusion resistance. We use a Bloom filter to achieve efficient matching. Second, we leverage privacy-preserving range query and Merkle proofs to make matching results verifiable. Meanwhile, we adopt short group signatures to provide anonymous authentication and deposit commitments to hold the runaway driver accountable. We formally state and prove the security and privacy of Nereus. We build a prototype based on Ethereum and SGX to conduct extensive performance analysis in regard to gas costs, computational costs, and communication overhead. Experimental results show that Nereus significantly improves over existing schemes in terms of computational costs.

Efficient Attribute-Based Signature With Collusion Resistance for Internet of Vehicles

Internet of Vehicles (IoV) realizes information interaction between vehicles and all networked entities, and the heterogeneous, openness, and diversity make it suffer from various security challenges such as authentication and access control problems. Attribute-based signature (ABS) is a promising cryptographic tool for addressing the above concerns, however, some existing ABS schemes take heavy computation overheads for signature verification. Though some server-aided ABS schemes are proposed to enhance performance, those schemes suffer from devastating collusion attacks. In addition, current signature-policy ABS schemes only support the single threshold access policy, which fails to meet various access control requirements of IoV. To address the above problems, we propose an efficient server-aided ABS with collusion resistance (SAABS-CR) for IoV. It utilizes server-aided computation technology to mitigate the computation burden of verifiers, while resisting perfectly the collusion attacks that include between signers and between the signer and the aided server. Moreover, SAABS-CR supports flexible expressions of access policy under the signature-policy framework by using the linear secret-sharing scheme (LSSS), and it is proved to be secure in the security model of strong unforgeability against chosen-message attacks (SU-CMA). Theoretical analyses and experimental evaluations show that SAABS-CR improves efficiency by reducing the time cost of signature generation at least 34.8% and user verification at least 15%.

A blockchain-based privacy-preserving and collusion-resistant scheme (PPCR) for double auctions

A blockchain-based privacy-preserving and collusion-resistant scheme (PPCR) for double auctions

A secure access control scheme with batch verification for VANETs

A secure access control scheme with batch verification for VANETs

Efficient Medical Data Transmission in Mobile Hospital Systems with Wireless Body Area Network

Wireless Body Area Networks (WBANs) are expected to play a major role in the field of patient- health monitoring shortly. One of the challenges is to establish secure communication architecture between sensors and users, whilst addressing the prevalent security and privacy concerns. In this paper, we propose communication architecture for BANs and design a scheme to secure the data communications between implanted /wearable sensors and the data sink/data consumers (doctors or nurses) by employing Cipher text-Policy Attribute-Based Encryption (CP-ABE) and signature to store the data in cipher text format at the data sink, hence ensuring data security. Our scheme achieves a role-based access control by employing an access control tree defined by the attributes of the data. We also design two protocols to securely retrieve the sensitive data from a BAN and instruct the sensors in a BAN. We analyze the proposed scheme and argue that it provides message authenticity and collusion resistance, and is efficient and feasible. We also evaluate its performance in terms of energy consumption and communication/computation overhead. Keywords: Wireless Body Area Networks, Encryption, data sink, secure data communication.

Identity-Based Key Management Scheme for Secure Discussion Group Establishment in DOSNs

Distributed online social network (DOSN) solves the challenges of single-point failure and user data privacy faced by traditional online social network (OSN). Online discussion group, allowing a user to facilitate the communications with other users, is one of the most important components of (D)OSN. Key management is the key technology to ensure the secure establishment of discussion groups in DOSNs. However, the existing key management schemes for secure discussion group establishment in DOSNs cannot meet the requirements of sender non-restriction, receiver controllability, round optimal, certificate freeness simultaneously. In this paper, we propose a novel key management scheme for secure discussion group establishment in DOSNs. In our scheme, any user could use our key management scheme to initialize a discussion group with a piece of discussion group information. Users who are interested in the group topic contained in the discussion group information can join and leave the discussion group at any time once the discussion group is initialized with one-round communication. Any user/sender can find the users that he/she wants to communicate with by looking up the discussion group information of a discussion group and then send encrypted messages to some or all of the users in the discussion group. Therefore, our scheme achieves sender non-restriction, receiver controllability, round optimal, certificate freeness simultaneously. Security analysis also shows that our scheme achieves confidentiality, authentication, full collusion resistance, known-key security and perfect forward security.