Efficient Key Management: Heuristics

Abstract

Key management in relation to handling updates has received a lot of attention in the cryptographic access control community because of the impact this has on performance and security. Certain schools of thought hold the belief that cryptographic key management should minimize the risk of security violations due to stolen keys by updating the entire hierarchy whenever any of the keys needs to be changed. On the other hand, other schools of thought hold that key updates typically involve data encryptions that are expensive and therefore it makes sense to reduce the number of keys updated at any time; particularly if the updates occur fairly frequently. We present an extension of the Akl and Taylor scheme, as an approach that minimizes the cost of key updates by reducing the number of keys that need to be replaced. We also consider the issue of adding or deleting keys from a hierarchy efficiently.