EVAWEB v2 : enhancing a web-based assessment system focused on non-repudiation use and teaching

Security is one of the main problems in web-based assessment systems, particularly guaranteeing non-repudiation of tests submissions. Authors have developed EVAWEB, a web-based assessment system that addresses this issue by using digital signatures. Moreover, the use of this technology in EVAWEB provides a real context to the students for learning digital signatures. In this paper, the enhancements that have been incorporated to EVAWEB in order to develop an improved second version of the system are presented.This work was partially supported by Universidad Carlos III de Madrid under 1ª Convocatoria de Apoyo a Experiencias de Innovación Docente Curso 2003-2004.Publicad

Search for Trust: An Analysis and Comparison of CA System Alternatives and Enhancements

The security of the Public Key Infrastructure has been reevaluated in response to Certification Authority (CA) compromise which resulted in the circulation of fraudulent certificates. These rogue certificates can and have been used to execute Man-in-the-Middle attacks and gain access to users’ sensitive information. In wake of these events, there has been a call for change to the extent of either securing the current system or altogether replacing it with an alternative design. This paper will explore the following proposals which have been put forth to replace or improve the CA system with the goal of aiding in the prevention and detection of MITM attacks and improving the trust infrastructure: Convergence, Perspectives, Mutually Endorsed Certification Authority Infrastructure (MECAI), DNS-Based Authentication of Named Entities (DANE), DNS Certification Authority Authorization (CAA) Resource Records, Public Key Pinning, Sovereign Keys, and Certificate Transparency. Provided are brief descriptions of each proposal, along with an indication of the pros and cons of each system. Following this, a new metric is applied which, according to a set of criteria, ranks each proposal and gives readers an idea of the costs and benefits of implementing the proposed system and the potential strengths and weaknesses of the design. We conclude with recommendations for further research and remark on the proposals with the most potential going forward

Certificate Transparency with Enhancements and Short Proofs

Browsers can detect malicious websites that are provisioned with forged or fake TLS/SSL certificates. However, they are not so good at detecting malicious websites if they are provisioned with mistakenly issued certificates or certificates that have been issued by a compromised certificate authority. Google proposed certificate transparency which is an open framework to monitor and audit certificates in real time. Thereafter, a few other certificate transparency schemes have been proposed which can even handle revocation. All currently known constructions use Merkle hash trees and have proof size logarithmic in the number of certificates/domain owners. We present a new certificate transparency scheme with short (constant size) proofs. Our construction makes use of dynamic bilinear-map accumulators. The scheme has many desirable properties like efficient revocation, low verification cost and update costs comparable to the existing schemes. We provide proofs of security and evaluate the performance of our scheme.Comment: A preliminary version of the paper was published in ACISP 201

Certificate Transparency with Enhancements and Short Proofs

Browsers can detect malicious websites that are provisioned with forged or fake TLS/SSL certificates. However, they are not so good at detecting malicious websites if they are provisioned with mistakenly issued certificates or certificates that have been issued by a compromised certificate authority. Google proposed certificate transparency which is an open framework to monitor and audit certificates in real time. Thereafter, a few other certificate transparency schemes have been proposed which can even handle revocation. All currently known constructions use Merkle hash trees and have proof size logarithmic in the number of certificates/domain owners. We present a new certificate transparency scheme with short (constant size) proofs. Our construction makes use of dynamic bilinear-map accumulators. The scheme has many desirable properties like efficient revocation, low verification cost and update costs comparable to the existing schemes. We provide proofs of security and evaluate the performance of our scheme.Comment: A preliminary version of the paper was published in ACISP 201

SoK: Delegation and Revocation, the Missing Links in the Web's Chain of Trust

The ability to quickly revoke a compromised key is critical to the security of any public-key infrastructure. Regrettably, most traditional certificate revocation schemes suffer from latency, availability, or privacy problems. These problems are exacerbated by the lack of a native delegation mechanism in TLS, which increasingly leads domain owners to engage in dangerous practices such as sharing their private keys with third parties. We analyze solutions that address the long-standing delegation and revocation shortcomings of the web PKI, with a focus on approaches that directly affect the chain of trust (i.e., the X.509 certification path). For this purpose, we propose a 19-criteria framework for characterizing revocation and delegation schemes. We also show that combining short-lived delegated credentials or proxy certificates with an appropriate revocation system would solve several pressing problems.Comment: IEEE European Symposium on Security and Privacy (EuroS&P) 202

Data privacy by design: digital infrastructures for clinical collaborations

The clinical sciences have arguably the most stringent security demands on the adoption and roll-out of collaborative e-Infrastructure solutions such as those based upon Grid-based middleware. Experiences from the Medical Research Council (MRC) funded Virtual Organisations for Trials and Epidemiological Studies (VOTES) project and numerous other real world security driven projects at the UK e-Science National e-Science Centre (NeSC – www.nesc.ac.uk) have shown that whilst advanced Grid security and middleware solutions now offer capabilities to address many of the distributed data and security challenges in the clinical domain, the real clinical world as typified by organizations such as the National Health Service (NHS) in the UK are extremely wary of adoption of such technologies: firewalls; ethics; information governance, software validation, and the actual realities of existing infrastructures need to be considered from the outset. Based on these experiences we present a novel data linkage and anonymisation infrastructure that has been developed with close co-operation of the various stakeholders in the clinical domain (including the NHS) that addresses their concerns and satisfies the needs of the academic clinical research community. We demonstrate the implementation of this infrastructure through a representative clinical study on chronic diseases in Scotland

A survey on cyber security for smart grid communications

A smart grid is a new form of electricity network with high fidelity power-flow control, self-healing, and energy reliability and energy security using digital communications and control technology. To upgrade an existing power grid into a smart grid, it requires significant dependence on intelligent and secure communication infrastructures. It requires security frameworks for distributed communications, pervasive computing and sensing technologies in smart grid. However, as many of the communication technologies currently recommended to use by a smart grid is vulnerable in cyber security, it could lead to unreliable system operations, causing unnecessary expenditure, even consequential disaster to both utilities and consumers. In this paper, we summarize the cyber security requirements and the possible vulnerabilities in smart grid communications and survey the current solutions on cyber security for smart grid communications. © 2012 IEEE