internal void checkProofs()
 {
     var nc = retrieveTotalCandidates();
     var pk = retrieveKey();
     var djn = new DJN.DJN(nc);
     var vids = retrieveVoteIDs();
     int count = 0;
     foreach (var vid in vids)
     {
         var vote = retrieveProofs(vid);
         var ok = false;
         if (vote.Item2.Item1.Length > 0)
         {
             ok = djn.checkProof(vote.Item1, vote.Item2, pk);
             if (ok) count++;
             setVoteValidity(vid, ok);
         }
         log("Vote with id:" + vid + (ok ? " is valid!" : " is invalid!"));
     }
     log("Num of valid votes = "+count);
 }