Formal Modelling of PBFT Consensus Algorithm in Event-B

Listing 17

Event ‘Prepare_check’.

 Event Prepare_check

   Any node m

   Where

    @grd1 node∈NODES

    @grd2 m∈ℕ×(ℕ×value)

    @grd3 prj1(prj2(m))−n∈0‥H

    @grd4 m∈union(ran(G_pre(node)))

    @grd5 ({i∣i∈dom(G_pre(node))∧m∈G_pre(node)(i)})≥2(NODES) +1

    @grd6 prj1(m)=view(node)

   Then

    @act1 G_pre_check(node)≔G_pre_check(node)∪{m}

 End