# Beaver triples {#beaver_triples}

ABY2.0-style sessions open masked wires once (Patra, Schneider, Suresh,
and Yalame, USENIX Security 2021 / [ePrint 2020/1225](@ref bib_aby2)).
A fresh triple follows Beaver, [CRYPTO 1991](@ref bib_beaver): both masked factors are
reconstructed, and the product share is a local correction.
Optional MAC tags are the Shark/SPDZ check.

One call that samples a list of formulae opens the new wires in one
round. Communication is one masked value per newly opened wire, plus a
tag share of the same width when MACs are on. Preprocessing is one blind
per wire and one product share per monomial.

**Go deeper:** [beaver.hpp](@ref dpf/beaver.hpp),
[F_Beaver](@ref beaver.hpp), [F_BeaverAuth](@ref beaver.hpp),
and the cost notes in the [guided tour](@ref tour_beaver).