Digital signatures provide authenticity and nonrepudiation. They are a standard cryptographic primitive with many applications in higher-level protocols. Groups featuring a computable bilinear map are particularly well suited for signature-related primitives. For some signature variants the only construction known uses bilinear maps. Where constructions based on, e.g., RSA are known, bilinear-m...

We examine the limitations on revocation approaches in VANETs, including local revocation and global revocation. Local revocation schemes often use a local vote to identify and revoke an attacker. However, such votes often require that not only a majority of local nodes are honest, but that they also are able to detect the attack. We argue that these requirements may not be practical, particula...

The diffi culty and expense of having a baby through surrogacy in the West is driving thousands of couples to India where a lack of red tape and highquality medical care means that the process is easy, cheap, and hassle-free. Commercial surrogacy was legalised in India in 2002, as part of the country’s drive to promote medical tourism, an industry that the Confederation of Indian Industry predi...

In access control frameworks with the possibility of delegating permissions and administrative rights, delegation chains can form. There are different ways to treat these delegation chains when revoking rights, which give rise to different revocation schemes. Hagström et al. [11] proposed a framework for classifying revocation schemes, in which the different revocation schemes are defined graph...

Group signatures allow users to anonymously sign messages in the name of a group. Membership revocation has always been a critical issue in such systems. In 2004, Boneh and Shacham formalized the concept of group signatures with verifier-local revocation where revocation messages are only sent to signature verifiers (as opposed to both signers and verifiers). This paper presents an efficient ve...

We present a new approach to fast certi cate revocation centered around the concept of an on-line semi-trusted mediator (SEM). The use of a SEM in conjunction with a simple threshold variant of the RSA cryptosystem (mediated RSA) o ers a number of practical advantages over current revocation techniques. Our approach simpli es validation of digital signatures and enables certi cate revocation wi...

The comparative approach regarding the ethics of surrogacy from the Western secular and Islamic bioethical view reveals both commensurable and incommensurable relationship. Both are eager to achieve the welfare of the mother, child and society as a whole but the approaches are not always the same. Islamic bioethics is straightforward in prohibiting surrogacy by highlighting the lineage problem ...

While Korea does not have any legal statement on surrogacy, treatments are carried out in practice. As a result, every Institutional Review Board (IRB) of each fertility clinic faces an ethical predicament in reviewing each case. There is a need to arrange the institutions' own standards of surrogate pregnancy procedures before the establishment of national or professional regulation. This arti...

A two-stage model for evaluating both trial-level and patient-level surrogacy of correlated time-to-event endpoints has been introduced, using patient-level data when multiple clinical trials are available. However, the associated maximum likelihood approach often suffers from numerical problems when different baseline hazards among trials and imperfect estimation of treatment effects are assum...

There has been great recent interest in the medical and statistical literature in the assessment and validation of surrogate endpoints as proxies for clinical endpoints in medical studies. More recently, authors have focused on using metaanalytical methods for quantification of surrogacy. In this article, we extend existing procedures for analysis based on the accelerated failure time model to ...