An Efficient Key Assignment Scheme Based on One-Way Hash Function in a User Hierarchy

摘要

In order to solve the problems resulted from dynamic access control in a user hierarchy, a cryptographic key assignment scheme is proposed by Prof. Lin to promote the performing ability and to simplify the procedure. However, it may cause the security in danger as the user changes his secret key; besides, some secret keys may be disclosed due to the unsuitable selection of the security classes' identities. Through setting up a one-way hash function onto Lin's scheme, the proposed modification can greatly improve the security of Lin's scheme.