The design of mechanisms to control the sharing of information in the Multics system is described. Five design principles help provide insight into the tradeoffs among different possible designs. The key mechanisms described include access control lists, hierarchical control of access specifications, identification and authentication of users, and primary memory protection. The paper ends with a discussion of several known weaknesses in the current protection mechanism design.

This chapter contains introductory and background information about cryptography and PGP as written by Phil Zimmermann.

In this article we offer guidelines for the determination of key sizes for symmetric cryptosystems, RSA, and discrete logarithm based cryptosystems both over finite fields and over groups of elliptic curves over prime fields. Our recommendations are based on a set of explicitly formulated hypotheses, combined with existing data points about the cryptosystems.

We propose a new distributed security infrastructure, called SDSI (pronounced "Sudsy"). SDSI combines a simple public-key infrastructure design with a means of defining groups and issuing group-membership certificates. SDSI's groups provides simple, clear terminology for defining access-control lists and security policies. SDSI's design emphasizes linked local name spaces rather than a hierarchical global name space.