Formal Modelling of PBFT Consensus Algorithm in Event-B

Listing 16

Event ‘Prepare’.

Event prepare

  Anym_c m_f send rec

  Where

   @grd1 send∈NODES∖{pre}

   @grd2 rec∈NODES

   @grd3 send≠rec

   @grd4 m_c∈ℕ×(ℕ×value)

   @grd5 m_c∈G_p(send)

   @grd6 prj1(prj2(m_c))−n∈0‥H

   @grd7 m_f∈ℕ×(ℕ×value)

   @grd8 prj1(m_f)=prj1(m_c)

   @grd9 prj2(prj2(m_f))∈Faulty_value

   @grd10 prj1(prj2(m_f))−n∈0‥H

   @grd11 send∈dom(G_pre(rec))

   @grd12 m_f∉G_pre(rec)(send)

   @grd13 m_c∉G_pre(rec)(send)

  Then

   @act1 G_pre≔{TRUE↦G_pre<+{rec↦G_pre(rec)∪{send↦{m_c}}},

FALSE↦G_pre<+{rec↦G_pre(rec)∪{send↦{m_f}}}}(bool(send∈corr))

 End