Visible to the public Biblio

Found 251 results

Filters: Keyword is Public key  [Clear All Filters]
2021-02-08
Pramanik, S., Bandyopadhyay, S. K., Ghosh, R..  2020.  Signature Image Hiding in Color Image using Steganography and Cryptography based on Digital Signature Concepts. 2020 2nd International Conference on Innovative Mechanisms for Industry Applications (ICIMIA). :665–669.
Data Transmission in network security is one of the most vital issues in today's communication world. The outcome of the suggested method is outlined over here. Enhanced security can be achieved by this method. The vigorous growth in the field of information communication has made information transmission much easier. But this type of advancement has opened up many possibilities of information being snooped. So, day-by-day maintaining of information security is becoming an inseparable part of computing and communication. In this paper, the authors have explored techniques that blend cryptography & steganography together. In steganography, information is kept hidden behind a cover image. In this paper, approaches for information hiding using both cryptography & steganography is proposed keeping in mind two considerations - size of the encrypted object and degree of security. Here, signature image information is kept hidden into cover image using private key of sender & receiver, which extracts the information from stego image using a public key. This approach can be used for message authentication, message integrity & non-repudiation purpose.
Van, L. X., Dung, L. H., Hoa, D. V..  2020.  Developing Root Problem Aims to Create a Secure Digital Signature Scheme in Data Transfer. 2020 International Conference on Green and Human Information Technology (ICGHIT). :25–30.
This paper presents the proposed method of building a digital signature algorithm which is based on the difficulty of solving root problem and some expanded root problems on Zp. The expanded root problem is a new form of difficult problem without the solution, also originally proposed and applied to build digital signature algorithms. This proposed method enable to build a high-security digital signature platform for practical applications.
2021-02-03
Kaneriya, J., Patel, H..  2020.  A Comparative Survey on Blockchain Based Self Sovereign Identity System. 2020 3rd International Conference on Intelligent Sustainable Systems (ICISS). :1150—1155.

The Internet has changed business, education, healthcare, banking etc. and it is the main part of technological evolution. Internet provides us a connecting world to perform our day to day life activities easily. Internet is designed in such a way that it can uniquely identify machine, not a person, on the network hence there is need to design a system that can perform entity identification on the Internet. Currently on Internet, service providers provide identity of a user with user name and password and store this information on a centralized server. These servers become honey pot for hackers to steal user’s personal identity information and service provider can utilize user identity information using data mining, artificial intelligence for economic benefits. Aim of Self sovereign identity system is to provide decentralized, user centric identity system which is controlled by identity owner that can be developed along with distributed ledger technology i.e. blockchain. In this paper, we intend to make an exhaustive study on different blockchain based self sovereign identity implementations (such as Sovrin, Uport, EverID, LifeID, Sora, SelfKey) along with its architectural components and discuss about use case of self sovereign identity.

2021-02-01
Kfoury, E. F., Khoury, D., AlSabeh, A., Gomez, J., Crichigno, J., Bou-Harb, E..  2020.  A Blockchain-based Method for Decentralizing the ACME Protocol to Enhance Trust in PKI. 2020 43rd International Conference on Telecommunications and Signal Processing (TSP). :461–465.

Blockchain technology is the cornerstone of digital trust and systems' decentralization. The necessity of eliminating trust in computing systems has triggered researchers to investigate the applicability of Blockchain to decentralize the conventional security models. Specifically, researchers continuously aim at minimizing trust in the well-known Public Key Infrastructure (PKI) model which currently requires a trusted Certificate Authority (CA) to sign digital certificates. Recently, the Automated Certificate Management Environment (ACME) was standardized as a certificate issuance automation protocol. It minimizes the human interaction by enabling certificates to be automatically requested, verified, and installed on servers. ACME only solved the automation issue, but the trust concerns remain as a trusted CA is required. In this paper we propose decentralizing the ACME protocol by using the Blockchain technology to enhance the current trust issues of the existing PKI model and to eliminate the need for a trusted CA. The system was implemented and tested on Ethereum Blockchain, and the results showed that the system is feasible in terms of cost, speed, and applicability on a wide range of devices including Internet of Things (IoT) devices.

2021-01-28
Fathi, Z., Rafsanjani, A. J., Habibi, F..  2020.  Anon-ISAC: Anonymity-preserving cyber threat information sharing platform based on permissioned Blockchain. 2020 28th Iranian Conference on Electrical Engineering (ICEE). :1—5.

In cyber threat information sharing, secure transfer and protecting privacy are very important. In this paper we solve these issues by suggesting a platform based on private permissioned Blockchain, which provides us with access control as well. The platform is called Anon-ISAC and is built on the Enhanced Privacy ID (EPID) zero-knowledge proof scheme. It makes use of permissioned Blockchain as a way to keep identity anonymous. Organizations can share their information on incidents or other artifacts among trusted parties, while they keep their identity hidden. This will save them from unwanted consequences of exposure of sensitive security information.

2021-01-25
Valocký, F., Puchalik, M., Orgon, M..  2020.  Implementing Asymmetric Cryptography in High-Speed Data Transmission over Power Line. 2020 11th IEEE Annual Ubiquitous Computing, Electronics Mobile Communication Conference (UEMCON). :0849–0854.
The article presents a proposal for implementing asymmetric cryptography, specifically the elliptic curves for the protection of high-speed data transmission in a corporate network created on the platform of PLC (Power Line Communications). The solution uses an open-source software library OpenSSL. As part of the design, an experimental workplace was set up, a DHCP and FTP server was established. The possibility of encryption with the selected own elliptic curve from the OpenSSL library was tested so that key pairs (public and private keys) were generated using a software tool. A shared secret was created between communication participants and subsequently, data encryption and decryption were performed.
Thinn, A. A., Thwin, M. M. S..  2020.  A Hybrid Solution for Confidential Data Transfer Using PKI, Modified AES Algorithm and Image as a Secret Key. 2020 IEEE Conference on Computer Applications(ICCA). :1–4.
Nowadays the provision of online services by government or business organizations has become a standard and necessary operation. Transferring data including the confidential or sensitive information via Internet or insecure network and exchange of them is also increased day by day. As a result, confidential information leakage and cyber threats are also heightened. Confidential information trading became one of the most profitable businesses. Encrypting the data is a solution to secure the data from being exposed. In this paper, we would like to propose a solution for the secure transfer of data using symmetric encryption, asymmetric encryption technologies and Key Generation Server as a mixed hybrid solution. A Symmetric encryption, modified AES algorithm, is used to encrypt data. Digital certificate is used both for data encryption and digital signing to assure data integrity. Key generation server is used to generate the second secret key from the publicly recognized information of a person and this key is used as a second secret key in the modified AES. The proposed hybrid solution can be utilized in any applications that require high confidentiality, integrity of data and non-repudiation.
Abusukhon, A., AlZu’bi, S..  2020.  New Direction of Cryptography: A Review on Text-to-Image Encryption Algorithms Based on RGB Color Value. 2020 Seventh International Conference on Software Defined Systems (SDS). :235–239.
Data encryption techniques are important for answering the question: How secure is the Internet for sending sensitive data. Keeping data secure while they are sent through the global network is a difficult task. This is because many hackers are fishing these data in order to get some benefits. The researchers have developed various types of encryption algorithms to protect data from attackers. These algorithms are mainly classified into two categories namely symmetric and asymmetric encryption algorithms. This survey sheds light on the recent work carried out on encrypting a text into an image based on the RGB color value and held a comparison between them based on various factors evolved from the literature.
Marasco, E. O., Quaglia, F..  2020.  AuthentiCAN: a Protocol for Improved Security over CAN. 2020 Fourth World Conference on Smart Trends in Systems, Security and Sustainability (WorldS4). :533–538.
The continuous progress of electronic equipments has influenced car manufacturers, leading to the integration of the latest infotainment technologies and providing connection to external devices, such as mobile phones. Modern cars work with ECUs (Electronic Control Units) that handle user interactions and sensor data, by also sending information to actuators using simple, reliable and efficient networks with fast protocols, like CAN (Controller Area Network). This is the most used vehicular protocol, which allows interconnecting different ECUs, making them interact in a synergic manner. On the down side, there is a security risk related to the exposition of malicious ECU's frames-possibly generated by compromised devices-which can lead to the possibility to remote control all the car equipments (like brakes and others) by an attacker. We propose a solution to this problem, designing an authentication and encryption system above CAN, called AuthentiCAN. Our proposal is tailored for the evolution of CAN called CAN-FD, and avoids the possibility for an attacker to inject malicious frames that are not discarded by the destination ECUs. Also, we avoid the possibility for an attacker to learn the interactions that occur across ECUs, with the objective of maliciously replaying messages-which would lead the actuator's logic to be no longer compliant with the actual data sources. We also present a simulation study of our solution, where we provide an assessment of its overhead, e.g. in terms of reduction of the throughput of data-unit transfer over CAN-FD, caused by the added security features.
2020-12-01
Goel, A., Agarwal, A., Vatsa, M., Singh, R., Ratha, N..  2019.  DeepRing: Protecting Deep Neural Network With Blockchain. 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW). :2821—2828.

Several computer vision applications such as object detection and face recognition have started to completely rely on deep learning based architectures. These architectures, when paired with appropriate loss functions and optimizers, produce state-of-the-art results in a myriad of problems. On the other hand, with the advent of "blockchain", the cybersecurity industry has developed a new sense of trust which was earlier missing from both the technical and commercial perspectives. Employment of cryptographic hash as well as symmetric/asymmetric encryption and decryption algorithms ensure security without any human intervention (i.e., centralized authority). In this research, we present the synergy between the best of both these worlds. We first propose a model which uses the learned parameters of a typical deep neural network and is secured from external adversaries by cryptography and blockchain technology. As the second contribution of the proposed research, a new parameter tampering attack is proposed to properly justify the role of blockchain in machine learning.

2020-10-29
Dholey, Milan Kumar, Biswas, G. P..  2018.  Secure DSR Routing from Malicious Node by PGP Encryption. 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI). :1449—1453.

Mobile ad hoc network (MANET) is an infrastructure less, self organizing on demand wireless communication. The nodes communicate among themselves through their radio range and nodes within the range are known as neighbor nodes. DSR (Dynamic Source Routing), a MANET reactive routing protocol identify the destination by transmitting route request (RREQ) control message into the network and establishes a path after receiving route reply (RREP) control messages. The intermediate node lies in between source to destination may also send RREP control message, weather they have path information about that destination is present into their route cache due to any previous communication. A malicious node may enter within the network and may send RREP control message to the source before original RREP is being received. After receiving RREP without knowing about the destination source starts to send data and data may reached to a different location. In this paper we proposed a novel algorithm by which a malicious node, even stay in the network and send RREP control message but before data transmission source can authenticate the destination by applying PGP (pretty Good Privacy) encryption program. In order to design our algorithm we proposed to add an extra field with RREQ control message with a unique index value (UIV) and two extra fields in RREP applied over UIV to form a random key (Rk) in such a way that, our proposal can maintained two way authorization scheme. Even a malicious node may exists into the network but before data transmission source can identified weather RREP is received by the requested destination or a by a malicious node.

Chauhan, Gargi K, Patel, Saurabh M.  2018.  Public String Based Threshold Cryptography (PSTC) for Mobile Ad Hoc Networks (MANET). 2018 Second International Conference on Intelligent Computing and Control Systems (ICICCS). :1—5.
Communication is an essential part of everyday life, both as a social interaction and collaboration to achieve goals. Wireless technology has effectively release the users to roam more freely to achieving collaboration and communication. The principle attraction of mobile ad hoc networks (MANET) are their set-up less and decentralized action. However, mobile ad hoc networks are seen as relatively easy targets for attackers. Security in mobile ad hoc network is provided by encrypting the data when exchanging messages and key management. Cryptography is therefore vital to ensure privacy of message and robustness against disruption. The proposed scheme public string based threshold cryptography (PSTC) describes the new scheme based on threshold cryptography that provides reasonably secure and robust cryptography scheme for mobile ad hoc networks. The scheme is implemented and simulated in ns-2. The scheme is based on trust value and analyze against Denial of Service attack as node found the attacker, the node reject all packet from that attacker. In proposed scheme whole network is compromised only when all nodes of network is compromised because threshold nodes only sharing public string not the master private key. The scheme provides confidentiality and integrity. The default threshold value selected is 2 according to time and space analysis.
2020-09-28
Dong, Guishan, Chen, Yuxiang, Fan, Jia, Liu, Dijun, Hao, Yao, Wang, Zhen.  2018.  A Privacy-User-Friendly Scheme for Wearable Smart Sensing Devices Based on Blockchain. 2018 IEEE 15th International Conference on Mobile Ad Hoc and Sensor Systems (MASS). :481–486.
Wearable smart sensing devices presently become more and more popular in people's daily life, which also brings serious problems related to personal data privacy. In order to provide users better experiences, wearable smart sensing devices are collecting users' personal data all the time and uploading the data to service provider to get computing services, which objectively let service provider master each user's condition and cause a lot of problems such as spam, harassing call, etc. This paper designs a blockchain based scheme to solve such problems by cutting off the association between user identifier and its sensing data from perspective of shielding service providers and adversaries. Firstly, privacy requirements and situations in smart sensing area are reviewed. Then, three key technologies are introduced in the scheme including its theories, purposes and usage. Next, the designed protocol is shown and analyzed in detail. Finally, security analysis and engineering feasibility of the scheme are given. This scheme will give user better experience from privacy protection perspective in smart sensing area.
Fimiani, Gianluca.  2018.  Supporting Privacy in a Cloud-Based Health Information System by Means of Fuzzy Conditional Identity-Based Proxy Re-encryption (FCI-PRE). 2018 32nd International Conference on Advanced Information Networking and Applications Workshops (WAINA). :569–572.
Healthcare is traditionally a data-intensive domain, where physicians needs complete and updated anamnesis of their patients to take the best medical decisions. Dematerialization of the medical documents and the consequent health information systems to share electronic health records among healthcare providers are paving the way to an effective solution to this issue. However, they are also paving the way of non-negligible privacy issues that are limiting the full application of these technologies. Encryption is a valuable means to resolve such issues, however the current schemes are not able to cope with all the needs and challenges that the cloud-based sharing of electronic health records imposes. In this work we have investigated the use of a novel scheme where encryption is combined with biometric authentication, and defines a preliminary solution.
2020-09-21
Vasile, Mario, Groza, Bogdan.  2019.  DeMetrA - Decentralized Metering with user Anonymity and layered privacy on Blockchain. 2019 23rd International Conference on System Theory, Control and Computing (ICSTCC). :560–565.
Wear and tear are essential in establishing the market value of an asset. From shutter counters on DSLRs to odometers inside cars, specific counters, that encode the degree of wear, exist on most products. But malicious modification of the information that they report was always a concern. Our work explores a solution to this problem by using the blockchain technology, a layered encoding of product attributes and identity-based cryptography. Merging such technologies is essential since blockchains facilitate the construction of a distributed database that is resilient to adversarial modifications, while identity-based signatures set room for a more convenient way to check the correctness of the reported values based on the name of the product and pseudonym of the owner alone. Nonetheless, we reinforce security by using ownership cards deployed around NFC tokens. Since odometer fraud is still a major practical concern, we discuss a practical scenario centered on vehicles, but the framework can be easily extended to many other assets.
2020-09-04
Teng, Jikai, Ma, Hongyang.  2019.  Dynamic asymmetric group key agreement protocol with traitor traceability. IET Information Security. 13:703—710.
In asymmetric group key agreement (ASGKA) protocols, a group of users establish a common encryption key which is publicly accessible and compute pairwise different decryption keys. It is left as an open problem to design an ASGKA protocol with traitor traceability in Eurocrypt 2009. A one-round dynamic authenticated ASGKA protocol with public traitor traceability is proposed in this study. It provides a black-box tracing algorithm. Ind-CPA security with key compromise impersonation resilience (KCIR) and forward secrecy of ASGKA protocols is formally defined. The proposed protocol is proved to be Ind-CPA secure with KCIR and forward secrecy under D k-HDHE assumption. It is also proved that the proposed protocol resists collusion attack. In Setup algorithm and Join algorithm, one communication round is required. In Leave algorithm, no message is required to be transmitted. The proposed protocol adopts O(log N)-way asymmetric multilinear map to make the size of public key and the size of ciphertext both achieve O(logN), where N is the number of potential group members. This is the first ASGKA protocol with public traitor traceability which is more efficient than trivial construction of ASGKA protocols.
2020-08-13
Xu, Ye, Li, Fengying, Cao, Bin.  2019.  Privacy-Preserving Authentication Based on Pseudonyms and Secret Sharing for VANET. 2019 Computing, Communications and IoT Applications (ComComAp). :157—162.
In this paper, we propose a conditional privacy-preserving authentication scheme based on pseudonyms and (t,n) threshold secret sharing, named CPPT, for vehicular communications. To achieve conditional privacy preservation, our scheme implements anonymous communications based on pseudonyms generated by hash chains. To prevent bad vehicles from conducting framed attacks on honest ones, CPPT introduces Shamir (t,n) threshold secret sharing technique. In addition, through two one-way hash chains, forward security and backward security are guaranteed, and it also optimize the revocation overhead. The size of certificate revocation list (CRL) is only proportional to the number of revoked vehicles and irrelated to how many pseudonymous certificates are held by the revoked vehicles. Extensive simulations demonstrate that CPPT outperforms ECPP, DCS, Hybrid and EMAP schemes in terms of revocation overhead, certificate updating overhead and authentication overhead.
2020-08-10
Mansour, Ahmad, Malik, Khalid M., Kaso, Niko.  2019.  AMOUN: Lightweight Scalable Multi-recipient Asymmetric Cryptographic Scheme. 2019 IEEE 9th Annual Computing and Communication Workshop and Conference (CCWC). :0838–0846.
Securing multi-party communication is very challenging particularly in dynamic networks. Existing multi-recipient cryptographic schemes pose variety of limitations. These include: requiring trust among all recipients to make an agreement, high computational cost for both encryption and decryption, and additional communication overhead when group membership changes. To overcome these limitations, this paper introduces a novel multi-recipient asymmetric cryptographic scheme, AMOUN. This scheme enables the sender to possibly send different messages in one ciphertext to multiple recipients to better utilize network resources, while ensuring that each recipient only retrieves its own designated message. Security analysis demonstrates that proposed scheme is secure against well-known attacks. Evaluation results demonstrate that lightweight AMOUN outperforms RSA and Multi-RSA in terms of computational cost for both encryption and decryption. For a given prime size, in case of encryption, AMOUN achieves 86% and 98% lower average computational cost than RSA and Multi-RSA, respectively; while for decryption, it shows performance improvement of 98% compared to RSA and Multi-RSA.
Qin, Hao, Li, Zhi, Hu, Peng, Zhang, Yulong, Dai, Yuwen.  2019.  Research on Point-To-Point Encryption Method of Power System Communication Data Based on Block Chain Technology. 2019 12th International Conference on Intelligent Computation Technology and Automation (ICICTA). :328–332.
Aiming at the poor stability of traditional communication data encryption methods, a point-to-point encryption method of power system communication data based on block chain technology is studied and designed. According to the principle of asymmetric key encryption, the design method makes use of the decentralization and consensus mechanism of block chain technology to develop the public key distribution scheme. After the public key distribution is completed, the sender and receiver of communication data generate the transfer key and pair the key with the public key to realize the pairing between data points. Xor and modular exponentiation are performed on the communication data content, and prime Numbers are used to fill the content data block. The receiver decrypts the data according to the encryption identifier of the data content, and completes the design of the encryption method of communication data point to ground. Through the comparison with the traditional encryption method, it is proved that the larger the amount of encrypted data is, the more secure the communication data can be, and the stability performance is better than the traditional encryption method.
2020-08-03
Seetharaman, R., Subramaniam, L.Harihara, Ramanathan, S..  2019.  Mobile Ad Hoc Network for Security Enhancement. 2019 2nd International Conference on Power and Embedded Drive Control (ICPEDC). :279–282.

This project enhances the security in which Ad Hoc On-Demand Distance Vector (AODV) routing protocol for MANETs with the game theoretical approach. This is achieved by using public key and private key for encryption and decryption processes. Proactive and reactive method is implemented in the proposed system. Reactive method is done in identification process but in proactive method is used to identify the nodes and also block the hackers node, then change the direction of data transmission to good nodes. This application can be used in military, research, confidential and emergency circumferences.

2020-07-24
Munsyi, Sudarsono, Amang, Harun Al Rasvid, M. Udin.  2018.  An Implementation of Data Exchange in Environmental Monitoring Using Authenticated Attribute-Based Encryption with Revocation. 2018 International Electronics Symposium on Knowledge Creation and Intelligent Computing (IES-KCIC). :359—366.
Internet of things era grown very rapidly in Industrial Revolution 4.0, there are many researchers use the Wireless Sensor Network (WSN) technology to obtain the data for environmental monitoring. The data obtained from WSN will be sent to the Data Center, where users can view and collect all of data from the Data Center using end devices such as personal computer, laptop, and mobile phone. The Data Center would be very dangerous, because everyone can intercept, track and even modify the data. Security requirement to ensure the confidentiality all of stored data in the data center and give the authenticity in data has not changed during the collection process. Ciphertext Policy Attribute-Based Encryption (CP-ABE) can become a solution to secure the confidentiality for all of data. Only users with appropriate rule of policy can get the original data. To guarantee there is no changes during the collection process of the data then require the time stamp digital signature for securing the data integrity. To protect the confidentiality and data integrity, we propose a security mechanism using CP-ABE with user revocation and Time Stamp Digital Signature using Elliptic Curve Cryptography (ECC) 384 bits. Our system can do the revocation for the users who did the illegal access. Our system is not only securing the data but also providing the guarantee that is no changes during the collection process of the data from the Data Center.
Jiang, Feng, Qi, Buren, Wu, Tianhao, Zhu, Konglin, Zhang, Lin.  2019.  CPSS: CP-ABE based Platoon Secure Sensing Scheme against Cyber-Attacks. 2019 IEEE Intelligent Transportation Systems Conference (ITSC). :3218—3223.

Platoon is one of cooperative driving applications where a set of vehicles can collaboratively sense each other for driving safety and traffic efficiency. However, platoon without security insurance makes the cooperative vehicles vulnerable to cyber-attacks, which may cause life-threatening accidents. In this paper, we introduce malicious attacks in platoon maneuvers. To defend against these attacks, we propose a Cyphertext-Policy Attribute-Based Encryption (CP-ABE) based Platoon Secure Sensing scheme, named CPSS. In the CPSS, platoon key is encapsulated in the access control structure in the key distribution process, so that interference messages sending by attackers without the platoon key could be ignored. Therefore, the sensing data which contains speed and position information can be protected. In this way, speed and distance fluctuations caused by attacks can be mitigated even eliminated thereby avoiding the collisions and ensuring the overall platoon stability. Time complexity analysis shows that the CPSS is more efficient than that of the polynomial time solutions. Finally, to evaluate capabilities of the CPSS, we integrate a LTE-V2X with platoon maneuvers based on Veins platform. The evaluation results show that the CPSS outperforms the baseline algorithm by 25% in terms of distance variations.

Wang, Fucai, Shi, Ting, Li, Shijin.  2019.  Authorization of Searchable CP-ABE Scheme with Attribute Revocation in Cloud Computing. 2019 IEEE 8th Joint International Information Technology and Artificial Intelligence Conference (ITAIC). :204—208.

Most searchable attribute-based encryption schemes only support the search for single-keyword without attribute revocation, the data user cannot quickly detect the validity of the ciphertext returned by the cloud service provider. Therefore, this paper proposes an authorization of searchable CP-ABE scheme with attribute revocation and applies the scheme to the cloud computing environment. The data user to send the authorization information to the authorization server for authorization, assists the data user to effectively detect the ciphertext information returned by the cloud service provider while supporting the revocation of the user attribute in a fine-grained access control structure without updating the key during revocation stage. In the random oracle model based on the calculation of Diffie-Hellman problem, it is proved that the scheme can satisfy the indistinguishability of ciphertext and search trapdoor. Finally, the performance analysis shows that the scheme has higher computational efficiency.

Porwal, Shardha, Mittal, Sangeeta.  2019.  A Flexible Secure Key Delegation Mechanism for CP-ABE with Hidden Access Structure. 2019 11th International Conference on Information Technology and Electrical Engineering (ICITEE). :1—6.

Ciphertext Policy Attribute Based Encryption techniques provide fine grained access control to securely share the data in the organizations where access rights of users vary according to their roles. We have noticed that various key delegation mechanisms are provided for CP-ABE schemes but no key delegation mechanism exists for CP-ABE with hidden access policy. In practical, users' identity may be revealed from access policy in the organizations and unlimited further delegations may results in unauthorized data access. For maintaining the users' anonymity, the access structure should be hidden and every user must be restricted for specified further delegations. In this work, we have presented a flexible secure key delegation mechanism for CP-ABE with hidden access structure. The proposed scheme enhances the capability of existing CP-ABE schemes by supporting flexible delegation, attribute revocation and user revocation with negligible enhancement in computational cost.

Tan, Syh-Yuan, Yeow, Kin-Woon, Hwang, Seong Oun.  2019.  Enhancement of a Lightweight Attribute-Based Encryption Scheme for the Internet of Things. IEEE Internet of Things Journal. 6:6384—6395.

In this paper, we present the enhancement of a lightweight key-policy attribute-based encryption (KP-ABE) scheme designed for the Internet of Things (IoT). The KP-ABE scheme was claimed to achieve ciphertext indistinguishability under chosen-plaintext attack in the selective-set model but we show that the KP-ABE scheme is insecure even in the weaker security notion, namely, one-way encryption under the same attack and model. In particular, we show that an attacker can decrypt a ciphertext which does not satisfy the policy imposed on his decryption key. Subsequently, we propose an efficient fix to the KP-ABE scheme as well as extending it to be a hierarchical KP-ABE (H-KP-ABE) scheme that can support role delegation in IoT applications. An example of applying our H-KP-ABE on an IoT-connected healthcare system is given to highlight the benefit of the delegation feature. Lastly, using the NIST curves secp192k1 and secp256k1, we benchmark the fixed (hierarchical) KP-ABE scheme on an Android phone and the result shows that the scheme is still the fastest in the literature.