The vital importance of the relay protection system makes it difficult for attackers to attack it directly. This article points out an innovative indirect coordinated attack (ICA) against the relay, which is initiated by manipulating load-side power electronics to generate false signals, to induce relays to malfunction and thus override trip. First, this article analyzes the vulnerability of the load-side power electronic and the potential for manipulating it to cause relay to malfunction. Next, this article investigates the principles and consequences of two indirect attacks, resulting in the blocking or tripping of the directional overcurrent relay (DOCR), respectively. Notably, if these two indirect attacks are combined into the ICA, it can penetrate through multiple DOCRs, posing a considerable threat to the security of the power system. To cope with it, a defense strategy is proposed, which is to implement a blocking reasons identification technology (BRIT) as a built-in function in DOCRs. BRIT employs the recursive feature elimination method to select optimal features and then identifies the actual overcurrent signal based on bidirectional LSTMto defend against the faulty blocking caused by the ICA. Consequently, it prevents the tripping signal from causing more extensive damage. The performance of the ICA process and the defense strategy is validated using the CIGRE low-voltage microgrid example system.

Communications of IT boxes need control. For IT boxes standing on floors, the control is done by wiring the boxes to some machines that specialize in controlling communications. Since through the wires the controlling machines can see the addresses of the wired IT boxes, the control of communications is done by the controlling machines working on the address information. Today in a paradigm shift, IT boxes are more and more standing on intelligent and distributed software: hypervisors. However, the industry remains in a legacy momentum of controlling communications by hypervisors still working only on the address information. This is not only under using the intelligence of hypervisors in capturing the identities of the IT boxes standing on them, but worse, making some infamous problems associated with working on addresses to get inhered into the new way of life of networking.

We present protocols for fair exchange of electronic data (digital signatures, payment and confidential data) between two parties A and B. Novel properties of the proposed protocols include: 1) offline trusted third party (TTP), i.e., TTP does not take part in the exchange unless one of the parties behaves improperly; 2) only three message exchanges are required in the normal situation; 3) true fair exchange, i.e., either A and B obtain each other's data or no party receives anything useful; no loss can be incurred to a party no matter how maliciously the other party behaves during the exchange. This last property is in contrast to previously proposed protocols with offline TTP ([1] and [21]), where a misbehaving party may get another party's data while refusing to send his document to the other party, and the TTP can provide affidavits attesting to what happened during the exchange. To our knowledge, the protocols presented here are the first exchange protocols which use offline TTP and at the same time guarantee true fair exchange of digital messages. We introduce a novel cryptographic primitive, called the Certificate of Encrypted Message Being a Signature (CEMBS), as the basic building block of the fair exchange protocols. It is used to prove that an encrypted message is a certain party's signature on a public file, without revealing the signature. We also give two examples to show in detail how the certificate can be constructed.

Argues the necessity of universally verifiable secret sharing for secrets as individual users' cryptographic keys, and proposes protocols to realize such secret sharing for two most common public-key cryptosystems: discrete logarithm-based and integer factorization-based. The universal verifiability achieves the sharing of secrets with multiple third parties as shareholders using two-party protocols in which a single verifier, who can be anybody, can verify the correctness of the secret sharing for the (off-line) multiple shareholders. Several advantages result: (i) dropping of the honesty requirement on the verifier and the shareholders, (ii) dropping of the online availability requirement on the multiple shareholders, and (iii) the simplicity of two-party protocols which provide users with the freedom and flexibility to choose multiple shareholders they trust in real time of share distribution. The two-party protocols proposed offer a practical solution for secure data backup and key recovery services.

Recently, two major bankcard payment instrument operators VISA and MasterCard published specifications for securing bankcard payment transactions on open networks for open scrutiny. (VISA: Secure Transaction Technology, STT; MasterCard: Secure Electronic Payment Protocol, SEPP.) Based on their success in operating the existing on-line payment systems, both proposals use advanced cryptographic technologies to supply some security services that are well-understood to be inadequate in open networks, and otherwise specify systems similar to today's private-network versions. In this paper we reason that when an open network is used for underlying electronic commerce some subtle vulnerabilities will emerge and the two specifications are seen not in anticipation of them. A number of weaknesses are found as a result of missing and misuse of security services. Missing and misused services include: authentication, nonrepudiation, integrity, and timeliness, We identify problems and devise solutions while trying to keep, the current successful working style of financial institutions being respected.

We address a common problem of a series of logics for analysis of authentication protocols due to Burrows-Abadi-Needham (BAN), Gong-Needham-Yahalom (GNY), Abadi-Tuttle (AT) and Syverson-Van Oorschot (SVO). The problem can be referred to as that these logics lack a computationally accountable means to perform an important protocol analysis step, called protocol idealization which is to transform some protocol messages into logical formulas. Mistakes may easily occur during the idealization steps in these logics. We propose a rule-based technique to turn the protocol idealization into a job of symbolic manipulation of protocol syntax. The idea is to refine a big step of protocol message transformation in the previous BAN techniques into several smaller ones; each smaller step is simpler and hence easier to understand. Thus, the protocol idealization becomes less error-prone. A number of idealization examples are demonstrated. We hope that these intuitively appealing examples will invite further studies in the correctness of our rules-based technique for protocol idealization.

Various published authentication protocols that employ symmetric cryptographic algorithms are examined. A number of misconceptions found in the specification, design and implementation of these protocols are revealed. Some misconceptions are considered responsible for definite security flaws, while others are shown to cause weaknesses which may help in attacks on the cryptographic mechanisms. We identify an underlying problem and attempt a remedy by developing a methodology for the development of secure and strong authentication protocols.>

The pioneering and well-known work of M. Burrows, M. Abadi and R. Needham (1989), (the BAN logic) which dominates the area of security protocol analysis is shown to take an approach which is not fully formal and which consequently permits approval of dangerous protocols. Measures to make the BAN logic formal are then proposed. The formalisation is found to be desirable not only for its potential in providing rigorous analysis of security protocols, but also for its readiness for supporting a computer-aided fashion of analysis.>