free a,b: bitstring [private].

channel c.

query attacker(a); attacker(b).


let P(x:bitstring)=
   sync 1;
   out(c,x).

process
    in(c, t: bool); if t then P(a) else P(b)

(* EXPECTPV
RESULT not attacker(a[]) cannot be proved.
RESULT not attacker(b[]) cannot be proved.
0.004s (user 0.000s + system 0.004s), max rss 7596K
END *)
