A group of students would like to compute their average
grade - without revealing their individual grades to each other.
Herman's algorithm is a synchronous randomized protocol for achieving self-stabilization in a token ring consisting of N processes.
We analyse the average shape of binary search trees generated by sequences of random insertions and deletions. This is a classical problem in the theory of algorithms, in which a central concern is to ensure that the random trees generated within a particular scheme have low average height.
Anonymity is a key concept in computer security. It arises in a wide range of contexts, such as voting, blogging, making donations, passing on sensitive information, etc. A celebrated toy example illustrating anonymity is that of the ‘Dining Cryptographers protocol’ [ Chaum 1988 ]. Imagine that a certain number of cryptographers are sharing a meal at a restaurant around a circular table. As the end of the meal, the waiter announces that the bill has already been paid. The cryptographers conclude that it is either one of them who has paid, or the organisation that employs them. They resolve to determine which of the two alternatives is the case, with the proviso that for the former the identity of the payer should remain secret.
