1  /*
 2      Copyright 2018 0KIMS association.
 3  
 4      This file is part of circom (Zero Knowledge Circuit Compiler).
 5  
 6      circom is a free software: you can redistribute it and/or modify it
 7      under the terms of the GNU General Public License as published by
 8      the Free Software Foundation, either version 3 of the License, or
 9      (at your option) any later version.
10  
11      circom is distributed in the hope that it will be useful, but WITHOUT
12      ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13      or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14      License for more details.
15  
16      You should have received a copy of the GNU General Public License
17      along with circom. If not, see <https://www.gnu.org/licenses/>.
18  */
19  pragma circom 2.0.0;
20  
21  function pointAdd(x1,y1,x2,y2) {
22      var a = 168700;
23      var d = 168696;
24  
25      var res[2];
26      res[0] = (x1*y2 + y1*x2) / (1 + d*x1*x2*y1*y2);
27      res[1] = (y1*y2 - a*x1*x2) / (1 - d*x1*x2*y1*y2);
28      return res;
29  }
30  
31  function EscalarMulW4Table(base, k) {
32      var out[16][2];
33  
34      var i;
35      var p[2];
36  
37      var dbl[2] = base;
38  
39      for (i=0; i<k*4; i++) {
40          dbl = pointAdd(dbl[0], dbl[1], dbl[0], dbl[1]);
41      }
42  
43      out[0][0] = 0;
44      out[0][1] = 1;
45      for (i=1; i<16; i++) {
46          p = pointAdd(out[i-1][0], out[i-1][1], dbl[0], dbl[1]);
47          out[i][0] = p[0];
48          out[i][1] = p[1];
49      }
50  
51      return out;
52  }