Key-aggregate cryptosystems (KAC) have attracted significant attention from the research
community because of their elegance and efficiency in enforcing predefined access control …

Proxy Re-encryption (PRE) offers an efficient solution for enforcing access control on
outsourced data through delegation of decryption rights of a delegator to a delegatee …

We focus on proposing a threshold proxy re-encryption scheme for networks with resource
constrained devices. We show that the existing quorum controlled proxy re-encryption …

In this paper, we analyze the quorum controlled proxy re-encryption scheme proposed by
Jakobsson for the security. We show that the scheme is susceptible to collusion and cannot …

Cryptographic hierarchical access control is widely employed in systems that manage data
or resources. To meet scalability and high availability requirements, it is desirable that an …

In this paper, we focus on practically motivated flexibility requirements for the hierarchical
access control model, namely transitive exception and anti-symmetric exception …

Hierarchical access control is for scenarios where some users have access to more
organization data than others. In this paper, we propose an efficient key assignment scheme …

A cloud-based re-encryption scheme allows a semi-trusted cloud proxy to convert a
ciphertext under delegator's public-key into a ciphertext of delegatee's. However, for an …

A cryptographic access control scheme enforces access control policy of the data owner on
his encrypted data. Most widely used cryptographic access control mechanism is …