  We formalize Byzantine linearizability, a correctness condition that
specifies whether a concurrent object with a sequential specification is
resilient against Byzantine failures. Using this definition, we systematically
study Byzantine-tolerant emulations of various objects from registers. We focus
on three useful objects -- reliable broadcast, atomic snapshot, and asset
transfer. We prove that there is an $f$-resilient implementation of such
objects from registers with $n$ processes $f<\frac{n}{2}$.
