Improving an Anonymous and Provably Secure Authentication Protocol for a Mobile User

Algorithm 4

Role specification for session, goal, and environment.

role session (Ui, AS: agent,

SKuas: symmetric_key,

H, F: function)

def=

local H1, H2, R1, R2: channel (dy)

composition

user (Ui, AS, SKuas, H, F, H1, R1)

∧ applicationserver (Ui, AS, SKuas, H, F, H2, R2)

end role

role environment() def=

const ui, as: agent,

skuas: symmetric_key,

h, f: function,

cidi, yi, zi, t1, ys, zs, t3: text,

as_ui_y2,

sc1, sc2, sc3, sc4: protocol_id

intruder_knowledge = ui, as, h, f, cidi, yi, zi, t1, ys, zs, t3

composition

session(ui, as, skuas, h, f)

∧ session(i, as, skuas, h, f)

∧ session(ui, i, skuas, h, f)

end role

goal

secrecy_of sc1, sc2, sc3, sc4

authentication_on as_ui_y2

end goal

environment()