Formal Definition Of The Signed. Message Algorithm Before defining the Signed Message Algorithm formally, Lamport et al define a function choice(V), where V is a set [LL 82]. “If the set V contains a single element v, then choice(V) = v” [LL 82]. If V = Ø, then choice(V) returns a default value, and choice(v1, v2, ..., vi) for i ≥ 2, can be defined to deterministically return any of the vi or the default value [LL 82]. Lamport et al formally define the Signed Message Algorithm as “Algorithm SM(m). Initially, Vi = Ø.
