Algorithm 2. The process of task release and download

Require:k query requests, R, t

Ensure: Qualified service results

1: procedure = end;

2: {k values, R values, Tr} ← requester;

3: k query requests ← requester;

4: blockchain ← < Ti, R, t>;

5: agent download task;

6: the LSP ← the query request, the query result ← the LSP;

7. while task set running time <= Tr

8.   if all tasks in the task set are submitted and verified successfully then

9.     break

10.   else if service result is submitted and qualified then

11.     the single task ends;

12.    else the requester forcibly withdraws the task;

13.   end if

13. end while

14. return procedure