Support of membership revocation is a desirable functionality for any group signature scheme. Among the known revocation approaches, verifier-local revocation (VLR) seems to be the most flexible one, because it only requires the verifiers to possess some up-to-date revocation information, but not the signers. All of the contemporary VLR group signatures operate in the bilinear map setting, and ...

We consider the problem of efficient key management and user revocation in cryptographic file systems that allow shared access to files. A performanceefficient solution to user revocation in such systems is lazy revocation, a method that delays the re-encryption of a file until the next write to that file. We formalize the notion of key-updating schemes for lazy revocation, an abstraction to ma...

Support of membership revocation is a desirable functionality for any group signature scheme. Among the known revocation approaches, verifier-local revocation (VLR) seems to be the most flexible one, because it only requires the verifiers to possess some up-to-date revocation information, but not the signers. All of the contemporary VLR group signatures operate in the bilinear map setting, and ...

Secret Handshake is becoming an ever more popular research subject in the field of privacypreserving authentication protocols. Revocation of credentials in Secret Handshakes is a difficult challenge, as it mixes the conflicting requirements of tracing revoked users and of the untraceability and unlinkability of legitimate protocol players. The schemes proposed in the literature are either limit...

Public key infrastructure provides a promising foundation for verifying the authenticity of communicating parties and transferring trust over the internet. The key issue in public key infrastructure is how to process certificate revocations. Previous research in this aspect has concentrated on the tradeoffs that can be made among different revocation options. No rigorous efforts have been made ...

This paper presents a model to evaluate certificate revocation using certificate revocation lists (CRL's) of the X.509 standard. The model shows the relationship between the number of users managed by a Certificate Authorities (CA) and the size of the revocation lists, the computation power of the CA and the necessary bandwidth to access the revoked certificates.

Abstract Study question How surrogacy contracts provisions provide greater protection to the unborn children compared case of natural conception? Summary answer The right life child seems have a broader scope than it does in conception. What is known already contract usually contains provision according which surrogate will not terminate pregnancy unless her own at risk. On other hand, intended...

Digital certificates signed by trusted certification authorities (CAs) are used for multiple purposes, most commonly for secure binding of public keys to names and other attributes of their owners. Although a certificate usually includes an expiration time, it is not uncommon that a certificate needs to be revoked prematurely. For this reason, whenever a client (user or program) needs to assert...

BACKGROUND During a commercial surrogacy arrangement, the event of embryo transfer can be seen as the formal starting point of the arrangement. However, it is common for surrogates to undergo a failed attempt at pregnancy conception or missed conception after an embryo transfer. This paper attempts to argue that such failed attempts can be understood as a loss. It aims to reconstruct the experi...