Formal Modelling of PBFT Consensus Algorithm in Event-B

Listing 20

Event ‘Primary_change’.

 Event Primary_change refines Primary_change

  AnyS

  Where

   @grd1 S⊆dom(View_change(max(NODES∖Pre_set)))

   @grd2 ∀i·i∈S⇒union(ran(View_change))(i)=max(NODES∖Pre_set)

   @grd3 3(S)≥2(NODES) +1

  Then

   @act1 pre≔max(NODES∖Pre_set)

   @act2 Pre_change≔TRUE

End