free c:channel.
free s:bitstring [private].

table tbl(bitstring).

fun enc(bitstring,bitstring):bitstring.
reduc forall x:bitstring,y:bitstring; dec(enc(x,y),y) = x.

process
  new k1:bitstring;
  new k2:bitstring;
  insert tbl(k1);
  insert tbl(k2);
  get tbl(x:bitstring) [precise] in 
  out(c,x);
  out(c,choice[enc(s,(k1,k2)),s])

(* EXPECTPV
RESULT Observational equivalence is true.
0.028s (user 0.028s + system 0.000s), max rss 8824K
END *)
