INFS 767 Fall 2000

Homework Assignment 3

Due in class 11/30/00

Maximum 500 words. DO NOT EXCEED THIS LIMIT.

ANSWER ANY ONE AND ONLY ONE QUESTION.

1. In the B2B Secure Electronic Commerce lecture Jeremy Epstein identified the problem of providing end-to-end digital signatures as opposed to gateway-to-gateway digital signatures. Briefly explain the problem and discuss possible solutions.

2. Discuss the relationship between task-based, team-based and role-based access control from Roshan Thomas’ lecture. Please do not give me definitions of these. We already know the definitions. I am interested in analysis of their relationships.

3. In context of RCL2000 let us define a type 1 constraint to have the form |set|=0 and a type 2 constraint to have the form |set|=1. Discuss the differences in enforcing a type 1 constraint versus a type 2 constraint.