Algorithm 1 Algorithm description of escape guidance path developing

1: Input: $s_t$

2: Output: ${\mathbf{P}}_{st}^h$

3: Initialize: h = 1, node i = target node, node u = target node

4: while (node i != source node) do

5:  if node i has next trustable anchor node n then

6:   calculate the distance d between node i and node n

7:   add the path $p_h$ to ${\mathbf{P}}_{st}^h$

8:   h = h + 1

9:   node u = node i, node i = node n

10:  else

11:    node i = node u

12:  end if

13: end while

14: for j = 1 to h do

15:  sum all d in $p_h$, calculate result $d_{sum}$

16:  choose the shortest $d_{sum}$ as path $p_h$

17: end for

18: return ${\mathbf{P}}_{st}^h$