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
20/******
21
22SMTVerifierLevel
23
24This circuit has 1 hash
25
26Outputs according to the state.
27
28State        root
29=====        =======
30top          H'(child, sibling)
31i0           0
32iold         old1leaf
33inew         new1leaf
34na           0
35
36H' is the Hash function with the inputs shifted acordingly.
37
38*****/
39pragma circom 2.0.0;
40
41template SMTVerifierLevel() {
42    signal input st_top;
43    signal input st_i0;
44    signal input st_iold;
45    signal input st_inew;
46    signal input st_na;
47
48    signal output root;
49    signal input sibling;
50    signal input old1leaf;
51    signal input new1leaf;
52    signal input lrbit;
53    signal input child;
54
55    signal aux[2];
56
57    component proofHash = SMTHash2();
58    component switcher = Switcher();
59
60    switcher.L <== child;
61    switcher.R <== sibling;
62
63    switcher.sel <== lrbit;
64    proofHash.L <== switcher.outL;
65    proofHash.R <== switcher.outR;
66
67    aux[0] <== proofHash.out * st_top;
68    aux[1] <== old1leaf*st_iold;
69
70    root <== aux[0] + aux[1] + new1leaf*st_inew;
71}