free c:channel.

fun h(bitstring):bitstring.

const a,b:bitstring.

free k:bitstring [private].

event A(bitstring).
event B.

const ok,ko:bitstring.

not attacker(k).

query x:bitstring; event(A(x)).

query event(B).

process
  in(c,x:bitstring);
  if x = a
  then
    event A(a);
    out(c,ok)
  else
    out(c,ko)

(* EXPECTPV
RESULT not event(A(x_1)) is false.
RESULT not event(B) is true.
0.012s (user 0.000s + system 0.012s), max rss 7836K
END *)
