An improvement of a dynamic cryptographic key assignment scheme in a tree hierarchy
This paper shows how several security classes in Liaw-Wang-Lei's cryptographic key assignment scheme can collaborate to derive the secret key of their immediate ancestor in some cases. We also propose two schemes which are a slight modification of the proposed scheme to enhance the level of security. (C) 1999 Elsevier Science Ltd. All rights reserved.
access control cryptography data security multilevel