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
 20include "bitify.circom";
 21include "escalarmulfix.circom";
 22
 23template BabyAdd() {
 24    signal input x1;
 25    signal input y1;
 26    signal input x2;
 27    signal input y2;
 28    signal output xout;
 29    signal output yout;
 30
 31    signal beta;
 32    signal gamma;
 33    signal delta;
 34    signal tau;
 35
 36    var a = 168700;
 37    var d = 168696;
 38
 39    beta <== x1*y2;
 40    gamma <== y1*x2;
 41    delta <== (-a*x1+y1)*(x2 + y2);
 42    tau <== beta * gamma;
 43
 44    xout <-- (beta + gamma) / (1+ d*tau);
 45    (1+ d*tau) * xout === (beta + gamma);
 46
 47    yout <-- (delta + a*beta - gamma) / (1-d*tau);
 48    (1-d*tau)*yout === (delta + a*beta - gamma);
 49}
 50
 51template BabyDbl() {
 52    signal input x;
 53    signal input y;
 54    signal output xout;
 55    signal output yout;
 56
 57    component adder = BabyAdd();
 58    adder.x1 <== x;
 59    adder.y1 <== y;
 60    adder.x2 <== x;
 61    adder.y2 <== y;
 62
 63    adder.xout ==> xout;
 64    adder.yout ==> yout;
 65}
 66
 67
 68template BabyCheck() {
 69    signal input x;
 70    signal input y;
 71
 72    signal x2;
 73    signal y2;
 74
 75    var a = 168700;
 76    var d = 168696;
 77
 78    x2 <== x*x;
 79    y2 <== y*y;
 80
 81    a*x2 + y2 === 1 + d*x2*y2;
 82}
 83
 84// Extracts the public key from private key
 85template BabyPbk() {
 86    signal private input  in;
 87    signal         output Ax;
 88    signal         output Ay;
 89
 90    var BASE8[2] = [
 91        5299619240641551281634865583518297030282874472190772894086521144482721001553,
 92        16950150798460657717958625567821834550301663161624707787222815936182638968203
 93    ];
 94
 95    component pvkBits = Num2Bits(253);
 96    pvkBits.in <== in;
 97
 98    component mulFix = EscalarMulFix(253, BASE8);
 99
100    var i;
101    for (i=0; i<253; i++) {
102        mulFix.e[i] <== pvkBits.out[i];
103    }
104    Ax  <== mulFix.out[0];
105    Ay  <== mulFix.out[1];
106}