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In the era of Industry 4.0 and digital transformation, smart grid (SG) plays an important role in the construction of various smart places. Logs produced by electrical appliances recording power consumption within the grid contain private information and may be collected as evidence for the services of dispute resolution or digital forensics. Therefore, security of the logs is of paramount importance. Our work designs a blockchain-enabled log management scheme with nonrepudiation for SGs. In this article, we employ ciphertext-policy attribute-based encryption to establish a fine-grained access control of the logs, which addresses data confidentiality concern. In addition, we introduce a hybrid blockchain system generating novel signature chains, for achieving an efficient private log protection system with a lot of properties including data loss prevention, tamper resistance, immutability and nonrepudiation. Employing various cost-saving solutions, our scheme achieves an efficient communication with more functionalities and security features, compared with the predecessor works. [ABSTRACT FROM AUTHOR]

Securing messages and protecting them from tampering during transmission in wireless sensor networks is a challenging task. Using message authentication schemes provides security and authentication, but with a high computational and communication cost. Sensors are highly constrained in terms of computational capabilities and power consumption. Therefore, computation is divided into two phases: online (at the sensor) and offline (at a more powerful central node). Moreover, public keys are generated based on the identities to reduce communication overhead. In this article, we propose a message authentication scheme based on identity that uses online/offline signature. We prove that the scheme provides and protects the integrity of messages during the transmission of data over an insecure network. Our scheme is existential unforgeable against chosen message attack. [ABSTRACT FROM AUTHOR]

In this article, we present the first solution for multi-party certified email that achieves fairness and confidentiality without the intervention of a TTP but with blockchain support when problems arise. Our solution preserves the confidentiality of the mail exchanged between the sender and the recipients even when the blockchain is involved. We provide a proof of concept implementation based on Ethereum smart contracts that shows it is feasible from a practical point of view. Because the functions of a smart contract are only executed on the blockchain in the case of conflict, costs are minimised compared to solutions that execute the functions on the blockchain in all cases (on-chain solutions). Moreover, the solution can be integrated into the existing email infrastructure.

In recent years, blockchain-related technologies and applications have gradually emerged. Blockchain technology is essentially a decentralized database maintained by the collective, and it is now widely applied in various fields. At the same time, with the growth of medical technology, medical information is becoming increasingly important in terms of patient identity background, medical payment records, and medical history. Medical information can be the most private information about a person, but due to issues such as operation errors within the network or a hacking attack by a malicious person, there have been major leaks of sensitive personal information in the past. In any case, this has become an issue worth studying to ensure the privacy of patients and protect these medical materials. On the other hand, under the current medical system, the patient's EMR (electronic medical record) cannot be searched across the hospital. When the patient attends the hospital for treatment, repeated examinations will occur, resulting in a waste of medical resources. Therefore, we propose a blockchain-based secure inter-hospital EMR sharing system in this article. Through the programmatic authorization mechanism by smart contracts, the security of EMR is guaranteed. In addition to the essential mutual authentication, the proposed scheme also provides and guarantees data integrity, nonrepudiation, user untraceability, forward and backward secrecy, and resistance to replay attack. [ABSTRACT FROM AUTHOR]

To enable today’s industrial automation, a significant number of sensors and actuators are required. In order to obtain trust and isolate faults in the data collected by this network, protection against authenticity fraud and nonrepudiation is essential. In this paper, we propose a very efficient symmetric-key-based security mechanism to establish authentication and nonrepudiation among all the nodes including the gateway in a distributed cooperative network, without communicating additional security parameters to establish different types of session keys. The solution also offers confidentiality and anonymity in case there are no malicious nodes. If at most one of the nodes is compromised, authentication and nonrepudiation still remain valid. Even if more nodes get compromised, the impact is limited. Therefore, the proposed method drastically differs from the classical group key management schemes, where one compromised node completely breaks the system. The proposed method is mainly based on a hash chain with multiple outputs defined at the gateway and shared with the other nodes in the network.

Emerging network computing technologies extend the functionalities of industrial IoT (IIoT) terminals. However, this promising service-provisioning scheme encounters problems in untrusted and distributed IIoT scenarios because malicious service providers or clients may deny service provisions or usage for their own interests. Traditional nonrepudiation solutions fade in IIoT environments due to requirements of trusted third parties or unacceptable overheads. Fortunately, the blockchain revolution facilitates innovative solutions. In this paper, we propose a blockchain-based fair nonrepudiation service provisioning scheme for IIoT scenarios in which the blockchain is used as a service publisher and an evidence recorder. Each service is separately delivered via on-chain and off-chain channels with mandatory evidence submissions for nonrepudiation purpose. Moreover, a homomorphic-hash-based service verification method is designed that can function with mere on-chain evidence. And an impartial smart contract is implemented to resolve disputes. The security analysis demonstrates the dependability, and the evaluations reveal the effectiveness and efficiency. [ABSTRACT FROM AUTHOR]

According to a recent World Health Organization report, people living in rural areas often lack access to medical resources and need to travel long distances to hospitals for medical treatment -- a situation which, until recently, seemed to have no solution. As communication and hardware technologies have rapidly developed in recent years, however, many services and applications integrating these technologies into daily life have come to form an Internet of Things (IoT), and this makes it possible to address the problem of access to medical services in rural areas. In addition, governments formulate policies in order to respond to rural healthcare requirements and can provide patrolling medical vehicle services to take care of residents in these remote areas. On the other hand, owing to the rapid development of human physiological sensing devices, people with chronic diseases or those who require long-term monitoring of physiological conditions can wear these physiological sensing devices, and the sensing data can be provided to rural medical vehicles, so that doctors can diagnose symptoms. People with complicated or severe conditions can go to large hospitals in urban areas for further diagnosis and treatment. However, a great deal of the information transmitted during these processes is sensitive data, which must therefore be protected with security protocols. Therefore, in this study, we propose an IoT-based rural medical monitoring system. The proposed scheme provides mutual authentication and guarantees data integrity, user untraceability, nonrepudiation, and forward and backward secrecy, in addition to being resistant to replay attack. [ABSTRACT FROM AUTHOR]

In this paper we propose to employ the concept of proof of violation (POV) for the response time auditing in the cloud. A POV scheme enables a user or a service provider to produce a precise proof of either the occurrence of the violation of properties or the innocence of the service provider. POV schemes are solutions for obtaining mutual nonrepudiation between users and the service provider in the cloud. To the best of our knowledge, it is the first scheme that can perform response time auditing according to cryptographic evidences without the need of a delivery agent. Experimental results are presented that demonstrate the feasibility of the proposed scheme. Service providers can use the proposed scheme to provide a mutual nonrepudiation guarantee for response time in their service-level agreements. [ABSTRACT FROM AUTHOR]

In this paper, we propose solution for obtaining mutual nonrepudiation between the user and service provider in cloud storage. One of the solutions for mutual nonrepudiation is based on logging attestations, which are signed messages. For supporting write-serializability and read freshness of files, an intuitive solution is to have attestations be chain hashed. However, it is inefficient when files in an account can be accessed by multiple client devices interchangeably because client devices must keep all the attestations or there must exist a way to broadcast the last attestation to all the client devices. We propose a scheme that can guarantee mutual nonrepudiation between the user and service provider without requiring the client devices to exchange any messages, and each client device only has to store the last attestation it received. Concurrent accesses of files should be forbidden if all attestations need to be chained together with one chain. We propose to use multiple chains to provide concurrent file accesses in a single account. In addition, we also propose how to apply the hash tree to remove accumulated attestations. The results from related experiments demonstrate the feasibility of the proposed scheme. A service provider of cloud storage can use the proposed scheme to provide a mutual nonrepudiation guarantee in their service-level agreement. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A very good method that can be used to protect a private network is the implementation of a firewall between Internet and Intranet. This firewall will filter the packets that transit the network according with the security policy defined at the system level. The SSL protocol allows verifying the identity of a WEB server based on a digital certificate issued by a certification authority. Secure data transport over the Internet is done by using encryption methods.

During a crisis, organisations face a major unpredictable event with potentially negative consequences. Effective information management and assurance can assist the organisation in making sure that they have the correct information in a secure format to make decisions to recover their operations. The main elements of effective information management and assurance are confidentiality, integrity and availability, combined with non-repudiation. Should an element of effective information management or assurance be removed it can have a detrimental effect on the other elements and render the information management and assurance practices of the organisation ineffectual. [ABSTRACT FROM AUTHOR]

SUMMARY The development of mobile signatures could increase the spread and adoption of mobile services based on electronic signatures, such as mobile payments, mobile business transactions, and mobile government services. A Mobile Signature Service (MSS) means that a user in any of the scenarios mentioned can attach an electronic signature, anywhere, anytime, as with a handwritten signature with a device that is almost always on him or her. Several solutions have appeared, such as using the European Telecommunications Standard Institute MSS, the Mobile Signature Application Unit, and the Mobile Network Operator-independent MSS. These solutions present two kinds of drawbacks. On the one hand, some of them require the service to be developed by all mobile network operators, whereas others are not based on efficient communications. In this paper, we present a new MSS named SIPmsign that solves these problems. Our proposal is based on the Session Initiation Protocol and defines how to exchange the information in a secure and more efficient way than previously. Thanks to Session Initiation Protocol, we provide the adoption of our proposal as a MSS for the new generation of mobile communications. In this paper, we also present the prototype we have developed as a proof of its feasibility as well as an evaluation of the performance of our solution. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A proxy signature scheme is a method which allows an original signer to delegate his signing authority to a designated person, called a proxy signer. Up to now, most of proxy signature schemes are based on the discrete logarithm problem. In this paper, we propose a proxy signature scheme and a threshold proxy signature scheme from the Weil pairing, and also provide a security proof. [ABSTRACT FROM AUTHOR]

Abstract: Many certificateless schemes have been proposed for different purposes, but as for as their applications in any electronic cash schemes there is still a lot of potential for strengthening the security aspect, and this paper is an attempt towards this. In this paper we propose a new type certificateless scheme which is applied for group oriented signcryption rather than a signature without using bilinear pairing, then a new E-cash system has been presented based on the proposed scheme. The salient feature of the proposed scheme is that any signcrypter of a group can signcrypt a document with the group manager and send it to the verifier. The verifier verifies the authenticity of the signcrypted text by using the group’s public parameters and cannot link a signcrypted text to the corresponding signcrypter. However, even the group manager or any signcrypter of that group alone cannot produce a valid signcrypted text. In case of any legal dispute, such as no repudiation of the signature, the group manager has the ability to reveal the identity of the signcrypter. The proposed scheme is secure against the indistinguishably chosen cipher text attack (IND-CCA). Unlinkability, unforgeability and traceability and its security are based on the two computationally hard problems, the Computational Diffie–Hellman Problem (CDHP) and Discrete Logarithmic Problem (DLP). The new scheme’s security analysis clearly suggests that it is very reliable to be used in security vulnerable applications in real life. [Copyright &y& Elsevier]

Current mobile pay-TV systems have two types of Conditional Access Systems (CAS): group-key-based and public-key systems. The best feature of group-key-based systems is the ability to enjoy the broadcast nature in delivery multimedia contents, while the major advantage of public-key systems is consolidating the security foundation to withstand various attacks, such as collusion attacks. However, the problems of group-key-based systems include collusion attacks, lack of nonrepudiation, and troublesome key distribution. Even worse, the benefit of broadcast efficiency is confined to a group size of no more than 512 subscribers. For public-key systems, the poor delivery scalability is the major shortcoming because the unique private key feature is only suitable for one-to-one delivery. In this article, we introduce a scalable access control scheme to integrate the merits of broadcasting regardless of group size and sound security assurance, including fine-grained access control and collusion attack resistance. For subscriber revocation, a single message is broadcast to the other subscribers to get the updated key, thus significantly boosting subscriber revocation scalability. Due to mobile subscribers' dynamic movements, this article also analyzes the benefit of retransmission cases in our system. Through the performance evaluation and functionality comparison, the proposed scheme should be a decent candidate to enhance the security strength and transmission efficiency in a mobile pay-TV system. [ABSTRACT FROM AUTHOR]

This paper presents a strong designated verifiable signcryption scheme, in which a message is signcrypted by a signcryptor and only a specific receiver, who called a "designated verifier", verifies it using his own secret key. The scheme is secure, as an adversary can not verify the signature even if the secret key of the signer is compromised or leaked. The security of the proposed scheme lies in the complexity of solving two computationally hard problems, namely, the Discrete Logarithm Problem (DLP) and the Integer Factorization Problem (IFP). The security analysis of the scheme has been done and it Is proved that, the proposed scheme can withstand an adaptive chosen ciphertext attack. This scheme can be very useful in organizations where there is a need to send confidential documents to a specific recipient. This scheme can also be applicable to real life scenarios, such as, e-commerce applications, e-banking and e-voting. [ABSTRACT FROM AUTHOR]

Nonrepudiation is currently legally supported by digital signatures. However, problems with digital signatures have been analyzed in several papers, which consequently create doubts for the signatures' ability to support nonrepudiation. The addressing of weaknesses of digital signatures through the use of biometrics has also been considered. The scope of this paper is the identification of the most suitable biometric technology to be used for nonrepudiation purposes. [ABSTRACT FROM AUTHOR]

The scope of this article is to evaluate the provision of nonrepudiation in electronic transactions. For the evaluation of the provision of nonrepudiation, two technological methods are compared: digital signatures and biometrics. [ABSTRACT FROM AUTHOR]

Nonrepudiation is a security service that plays an important role in many Internet applications. Traditional two-party nonrepudiation has been studied intensively in the literature. This survey focuses on multiparty scenarios and provides a comprehensive overview. It starts with a brief introduction of fundamental issues on nonrepudiation, including the types of nonrepudiation service and cryptographic evidence, the roles of trusted third-party, nonrepudiation phases and requirements, and the status of standardization. Then it describes the general multiparty nonrepudiation problem, and analyzes state-of-the-art mechanisms. After this, it presents in more detail the 1-N multiparty nonrepudiation solutions for distribution of different messages to multiple recipients. Finally, it discusses advanced solutions for two typical multiparty nonrepudiation applications, namely, multiparty certified email and multiparty contract signing. [ABSTRACT FROM AUTHOR]

As a network security researcher, the author finds it very disappointing that most users can't, or simply don't, secure their everyday Internet communications. For good reason, usability in security has received a fair deal of attention in the past few years. To push the issue further, the author decided to initiate his own informal case study on the usability and practical relevance of standard security mechanisms for email communication. The author focused my attention on available public-key cryptography techniques for digitally signing and encrypting email. His first step was to establish a public-private key pair to use with email. The author chose to use Secure/Multipurpose Internet Mail Extensions (S/MIME), a standard for signing and encrypting email, because it's already supported by popular email clients such as Apple Mail, Outlook Express, and Mozillas Thunderbird. Unlike S/MIME, the author found that pretty good privacy (PGP) and the GNU Privacy Guard (GPG) were unusable with nontechnical correspondents because it required them to install additional software. S/MIME, it seemed, was the better solution for these "everyday users", for whom the concepts of public-key infrastructure (PKI), PGP, certificates, keys, and so on remain elusive. Additionally, I decided to get my public key certified by Thawte (www.thawte.com), an online certificate authority (CA) [ABSTRACT FROM PUBLISHER]

Classical security protocols aim to achieve authentication and confidentiality under the assumption that the peers behave honestly. Some recent protocols are required to achieve their goals even if the peer misbehaves. Accountability is a protocol design strategy that may help. It delivers to peers sufficient evidence of each other's participation in the protocol. Accountability underlies the nonrepudiation protocol of Zhou and Gollmann and the certified email protocol of Abadi et al. This paper provides a comparative, formal analysis of the two protocols, and confirms that they reach their goals under realistic conditions. The treatment, which is conducted with mechanized support from the proof assistant Isabelle, requires various extensions to the existing analysis method. A byproduct is an account of the concept of higher-level protocol. [ABSTRACT FROM AUTHOR]

This article classifies common Internet banking authentication methods regarding potential threats and their level of security against common credential stealing and channel breaking attacks, respectively. The authors present two challenge/response Internet banking authentication solutions, one based on short-time passwords and one certificate-based, and relate them to the taxonomy above. There further outline how these solutions can be easily extended for nonrepudiation (that is, transaction signing), should more sophisticated content manipulation attacks become a real problem. Finally, they summarize their view on future requirements for secure Internet banking authentication and conclude by referencing real-live implementations [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, we propose a new (t,n) threshold proxy signature scheme, in which at least t out of n proxy signers delegated by the original signer can sign messages on behalf of the original signer. The proposed scheme has the following main properties: (i) Message recovery that the signing message is unnecessary to be transmitted and can be recovered from the proxy signature; (ii) Nonrepudiation that the verifier can identify the proxy group which is responsible for a threshold proxy signature; (iii) Traceability that the verifier can identify the actual proxy signers from the proxy group; (iv) Self-certified public keys that the authenticity of public keys can be verified without requiring any certificate and combined with the tasks of verifying of the proxy signature and recovering of the signing message in a single logical step. In addition, we propose an elliptic curve variant suitable for some cryptographic applications with limited computing power and storage space, e.g., smart card or Java card. As compared with the previous works based on the certificate-based public key system, the proposed schemes are more secure and efficient. [Copyright &y& Elsevier]

Digital evidence, such as digital signatures, is of crucial importance in the emerging digitally operating economy because it is easy to transmit, archive, search, and verify. Nevertheless, the initial promises of the usefulness of digital signatures were too optimistic. This calls for a systematic treatment of digital evidence. The goal of this paper is to provide a foundation for reasoning about digital evidence systems and legislation, thereby identifying the roles and limitations of digital evidence, in the apparently simple scenario where it should prove that an entity A agreed to a digital contract d. Our approach is in sharp contrast to the current general views documented in the technical literature amt in digital signature legislation. We propose an entirely new view of the concepts of certification, time stamping, revocation, and other trusted services, potentially leading to new and more sound business models for trusted services. Some of the perhaps provocative implications of our view are that certificates are generally irrelevant as evidence in a dispute, that it is generally irrelevant when a signature was generated, that a commitment to be liable for digital evidence cannot meaningfully be revoked, and that there is no need for mutually trusted authorities like certification authorities. We also propose a new type of digital evidence called digital declarations, based on a digital recording of a willful act indicating agreement to a document or contract. [ABSTRACT FROM AUTHOR]

The conflict between accepted modern cryptographic approaches to digital signatures and the venerable traditions of the law of signatures and the law of contracts has been well expounded over the last few years. During this year, hardware progress in public-key encryption has made it possible largely to bridge the gap between these two realms. This paper shows one way to do so. This is a promising time for cryptographic work on digital signatures, as well as for joint legal/cryptographic consideration of outstanding signature issues. [ABSTRACT FROM AUTHOR]

Recently, Sun et al. pointed out some weaknesses of Zhang’s threshold proxy signature scheme and a disadvantage of Kim’s threshold proxy signature scheme. They further proposed a new (t,n) threshold proxy signature scheme based on Zhang’s scheme to eliminate these drawbacks. Unfortunately, their scheme suffered from a weakness which is shown in this paper. The authors also propose an improvement to counter it. [Copyright &y& Elsevier]

To enable today's industrial automation, a significant number of sensors and actuators are required. In order to obtain trust and isolate faults in the data collected by this network, protection against authenticity fraud and nonrepudiation is essential. In this paper, we propose a very efficient symmetric-key-based security mechanism to establish authentication and nonrepudiation among all the nodes including the gateway in a distributed cooperative network, without communicating additional security parameters to establish different types of session keys. The solution also offers confidentiality and anonymity in case there are no malicious nodes. If at most one of the nodes is compromised, authentication and nonrepudiation still remain valid. Even if more nodes get compromised, the impact is limited. Therefore, the proposed method drastically differs from the classical group key management schemes, where one compromised node completely breaks the system. The proposed method is mainly based on a hash chain with multiple outputs defined at the gateway and shared with the other nodes in the network. [ABSTRACT FROM AUTHOR]

• The trust threshold value is adaptively calculated by applying machine learning technique. • Both BT and DT are considered. • Based on RQSR computation of the BT value is done. • RPSR is used to determine the RREP packet success rate. • TAAPML performance is evaluated with respect to PDR, Delay, residual energy and computational overhead of TMM. Security is a huge concern in the Internet of Things (IoT)-based Wireless Sensor Networks (WSNs). Authentication becomes critical in a highly secured environment and reliable communication, specifically trustworthiness. In security, nonrepudiation refers to a service, which provides proof of the origin of data and the integrity of the data. Hence, this factor is to be considered in an IoT environment. This work focuses on the proposed Trust Aggregation Authentication Protocol based on the Machine Learning technique (TAAPML). The total trust value is derived for each device from behavior and data trust values by the internet gateways. In the authentication phase, if either the trust value is less than a standard threshold value or the authentication token is invalid, then gateways omit that node. The trust threshold value is adaptively calculated by using a technique called Support Vector Machine (SVM) over the collected traffic data. TAAPML technique performance is evaluated with respect to Packet Delivery Ratio, Delay, Residual Energy, and Computational Overhead. [Display omitted] [ABSTRACT FROM AUTHOR]

The accountability of electronic commerce protocols is an important aspect to insures security of electronic transaction. This paper proposes to use Finite Automaton (FA) model as a new kind of framework to analyze the transaction protocols in the application of electronic commerce. [ABSTRACT FROM AUTHOR]