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 "montgomery.circom";
 21include "mux3.circom";
 22include "babyjub.circom";
 23
 24template Window4() {
 25    signal input in[4];
 26    signal input base[2];
 27    signal output out[2];
 28    signal output out8[2];   // Returns 8*Base (To be linked)
 29
 30    component mux = MultiMux3(2);
 31
 32    mux.s[0] <== in[0];
 33    mux.s[1] <== in[1];
 34    mux.s[2] <== in[2];
 35
 36    component dbl2 = MontgomeryDouble();
 37    component adr3 = MontgomeryAdd();
 38    component adr4 = MontgomeryAdd();
 39    component adr5 = MontgomeryAdd();
 40    component adr6 = MontgomeryAdd();
 41    component adr7 = MontgomeryAdd();
 42    component adr8 = MontgomeryAdd();
 43
 44// in[0]  -> 1*BASE
 45
 46    mux.c[0][0] <== base[0];
 47    mux.c[1][0] <== base[1];
 48
 49// in[1] -> 2*BASE
 50    dbl2.in[0] <== base[0];
 51    dbl2.in[1] <== base[1];
 52    mux.c[0][1] <== dbl2.out[0];
 53    mux.c[1][1] <== dbl2.out[1];
 54
 55// in[2] -> 3*BASE
 56    adr3.in1[0] <== base[0];
 57    adr3.in1[1] <== base[1];
 58    adr3.in2[0] <== dbl2.out[0];
 59    adr3.in2[1] <== dbl2.out[1];
 60    mux.c[0][2] <== adr3.out[0];
 61    mux.c[1][2] <== adr3.out[1];
 62
 63// in[3] -> 4*BASE
 64    adr4.in1[0] <== base[0];
 65    adr4.in1[1] <== base[1];
 66    adr4.in2[0] <== adr3.out[0];
 67    adr4.in2[1] <== adr3.out[1];
 68    mux.c[0][3] <== adr4.out[0];
 69    mux.c[1][3] <== adr4.out[1];
 70
 71// in[4] -> 5*BASE
 72    adr5.in1[0] <== base[0];
 73    adr5.in1[1] <== base[1];
 74    adr5.in2[0] <== adr4.out[0];
 75    adr5.in2[1] <== adr4.out[1];
 76    mux.c[0][4] <== adr5.out[0];
 77    mux.c[1][4] <== adr5.out[1];
 78
 79// in[5] -> 6*BASE
 80    adr6.in1[0] <== base[0];
 81    adr6.in1[1] <== base[1];
 82    adr6.in2[0] <== adr5.out[0];
 83    adr6.in2[1] <== adr5.out[1];
 84    mux.c[0][5] <== adr6.out[0];
 85    mux.c[1][5] <== adr6.out[1];
 86
 87// in[6] -> 7*BASE
 88    adr7.in1[0] <== base[0];
 89    adr7.in1[1] <== base[1];
 90    adr7.in2[0] <== adr6.out[0];
 91    adr7.in2[1] <== adr6.out[1];
 92    mux.c[0][6] <== adr7.out[0];
 93    mux.c[1][6] <== adr7.out[1];
 94
 95// in[7] -> 8*BASE
 96    adr8.in1[0] <== base[0];
 97    adr8.in1[1] <== base[1];
 98    adr8.in2[0] <== adr7.out[0];
 99    adr8.in2[1] <== adr7.out[1];
100    mux.c[0][7] <== adr8.out[0];
101    mux.c[1][7] <== adr8.out[1];
102
103    out8[0] <== adr8.out[0];
104    out8[1] <== adr8.out[1];
105
106    out[0] <== mux.out[0];
107    out[1] <== - mux.out[1]*2*in[3] + mux.out[1];  // Negate y if in[3] is one
108}
109
110
111template Segment(nWindows) {
112    signal input in[nWindows*4];
113    signal input base[2];
114    signal output out[2];
115
116    var i;
117    var j;
118
119    // Convert the base to montgomery
120
121    component e2m = Edwards2Montgomery();
122    e2m.in[0] <== base[0];
123    e2m.in[1] <== base[1];
124
125    component windows[nWindows];
126    component doublers1[nWindows-1];
127    component doublers2[nWindows-1];
128    component adders[nWindows-1];
129    for (i=0; i<nWindows; i++) {
130        windows[i] = Window4();
131        if (i==0) {
132            windows[i].base[0] <== e2m.out[0];
133            windows[i].base[1] <== e2m.out[1];
134        } else {
135            doublers1[i-1] = MontgomeryDouble();
136            doublers2[i-1] = MontgomeryDouble();
137            doublers1[i-1].in[0] <== windows[i-1].out8[0];
138            doublers1[i-1].in[1] <== windows[i-1].out8[1];
139            doublers2[i-1].in[0] <== doublers1[i-1].out[0];
140            doublers2[i-1].in[1] <== doublers1[i-1].out[1];
141
142            windows[i].base[0] <== doublers2[i-1].out[0];
143            windows[i].base[1] <== doublers2[i-1].out[1];
144
145            adders[i-1] = MontgomeryAdd();
146            if (i==1) {
147                adders[i-1].in1[0] <== windows[0].out[0];
148                adders[i-1].in1[1] <== windows[0].out[1];
149            } else {
150                adders[i-1].in1[0] <== adders[i-2].out[0];
151                adders[i-1].in1[1] <== adders[i-2].out[1];
152            }
153            adders[i-1].in2[0] <== windows[i].out[0];
154            adders[i-1].in2[1] <== windows[i].out[1];
155        }
156        for (j=0; j<4; j++) {
157            windows[i].in[j] <== in[4*i+j];
158        }
159    }
160
161    component m2e = Montgomery2Edwards();
162
163    if (nWindows > 1) {
164        m2e.in[0] <== adders[nWindows-2].out[0];
165        m2e.in[1] <== adders[nWindows-2].out[1];
166    } else {
167        m2e.in[0] <== windows[0].out[0];
168        m2e.in[1] <== windows[0].out[1];
169    }
170
171    out[0] <== m2e.out[0];
172    out[1] <== m2e.out[1];
173}
174
175template Pedersen(n) {
176    signal input in[n];
177    signal output out[2];
178
179    var BASE = [
180        [10457101036533406547632367118273992217979173478358440826365724437999023779287,19824078218392094440610104313265183977899662750282163392862422243483260492317],
181        [2671756056509184035029146175565761955751135805354291559563293617232983272177,2663205510731142763556352975002641716101654201788071096152948830924149045094],
182        [5802099305472655231388284418920769829666717045250560929368476121199858275951,5980429700218124965372158798884772646841287887664001482443826541541529227896],
183        [7107336197374528537877327281242680114152313102022415488494307685842428166594,2857869773864086953506483169737724679646433914307247183624878062391496185654],
184        [20265828622013100949498132415626198973119240347465898028410217039057588424236,1160461593266035632937973507065134938065359936056410650153315956301179689506],
185        [1487999857809287756929114517587739322941449154962237464737694709326309567994,14017256862867289575056460215526364897734808720610101650676790868051368668003],
186        [14618644331049802168996997831720384953259095788558646464435263343433563860015,13115243279999696210147231297848654998887864576952244320558158620692603342236],
187        [6814338563135591367010655964669793483652536871717891893032616415581401894627,13660303521961041205824633772157003587453809761793065294055279768121314853695],
188        [3571615583211663069428808372184817973703476260057504149923239576077102575715,11981351099832644138306422070127357074117642951423551606012551622164230222506],
189        [18597552580465440374022635246985743886550544261632147935254624835147509493269,6753322320275422086923032033899357299485124665258735666995435957890214041481]
190    ]
191
192    var nSegments = ((n-1)\200)+1;
193
194    component segments[nSegments];
195
196    var i;
197    var j;
198    var nBits;
199    var nWindows;
200    for (i=0; i<nSegments; i++) {
201        nBits = (i == (nSegments-1)) ? n - (nSegments-1)*200 : 200;
202        nWindows = ((nBits - 1)\4)+1;
203        segments[i] = Segment(nWindows);
204        segments[i].base[0] <== BASE[i][0];
205        segments[i].base[1] <== BASE[i][1];
206        for (j = 0; j<nBits; j++) {
207            segments[i].in[j] <== in[i*200+j];
208        }
209        // Fill padding bits
210        for (j = nBits; j < nWindows*4; j++) {
211            segments[i].in[j] <== 0;
212        }
213    }
214
215    component adders[nSegments-1];
216
217    for (i=0; i<nSegments-1; i++) {
218        adders[i] = BabyAdd();
219        if (i==0) {
220            adders[i].x1 <== segments[0].out[0];
221            adders[i].y1 <== segments[0].out[1];
222            adders[i].x2 <== segments[1].out[0];
223            adders[i].y2 <== segments[1].out[1];
224        } else {
225            adders[i].x1 <== adders[i-1].xout;
226            adders[i].y1 <== adders[i-1].yout;
227            adders[i].x2 <== segments[i+1].out[0];
228            adders[i].y2 <== segments[i+1].out[1];
229        }
230    }
231
232/*
233    coponent packPoint = PackPoint();
234
235    if (nSegments>1) {
236        packPoint.in[0] <== adders[nSegments-2].xout;
237        packPoint.in[1] <== adders[nSegments-2].yout;
238    } else {
239        packPoint.in[0] <== segments[0].out[0];
240        packPoint.in[1] <== segments[0].out[1];
241    }
242
243    out[0] <== packPoint.out[0];
244    out[1] <== packPoint.out[1];
245*/
246
247    if (nSegments>1) {
248        out[0] <== adders[nSegments-2].xout;
249        out[1] <== adders[nSegments-2].yout;
250    } else {
251        out[0] <== segments[0].out[0];
252        out[1] <== segments[0].out[1];
253    }
254}
255