free c0: bitstring [private].
free c1: bitstring.

restriction attacker(c0) ==> false.

channel c.

process
	in(c, x: bitstring); out(c, choice[c0,c1])

(* EXPECTPV
RESULT Diff-equivalence cannot be proved.
0.032s (user 0.008s + system 0.024s), max rss 8560K
END *)
