  This article presents a signature-free distributed algorithm which builds an
atomic read/write shared memory on top of an $n$-process asynchronous
message-passing system in which up to $t<n/3$ processes may commit Byzantine
failures. From a conceptual point of view, this algorithm is designed to be as
close as possible to the algorithm proposed by Attiya, Bar-Noy and Dolev (JACM
1995), which builds an atomic register in an $n$-process asynchronous
message-passing system where up to $t<n/2$ processes may crash. The proposed
algorithm is particularly simple. It does not use cryptography to cope with
Byzantine processes, and is optimal from a $t$-resilience point of view
($t<n/3$). A read operation requires $O(n)$ messages, and a write operation
requires $O(n^2)$ messages.
