circomlib/circuits/smt/smtprocessorlevel.circom
2018-12-16 11:27:29 +01:00

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/*
Copyright 2018 0KIMS association.
This file is part of circom (Zero Knowledge Circuit Compiler).
circom is a free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
circom is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for more details.
You should have received a copy of the GNU General Public License
along with circom. If not, see <https://www.gnu.org/licenses/>.
*/
/******
SMTProcessorLevel
This circuit has 2 hash
Outputs according to the state.
State oldRoot newRoot
===== ======= =======
top H'(oldChild, sibling) H'(newChild, sibling)
old0 0 new1leaf
bot old1leaf H'(newChild, 0)
new1 old1leaf H'(new1leaf, old1leaf)
na 0 0
upd old1leaf new1leaf
H' is the Hash function with the inputs shifted acordingly.
*****/
template SMTProcessorLevel() {
signal input st_top;
signal input st_old0;
signal input st_bot;
signal input st_new1;
signal input st_na;
signal input st_upd;
signal output oldRoot;
signal output newRoot;
signal input sibling;
signal input old1leaf;
signal input new1leaf;
signal input newlrbit;
signal input oldChild;
signal input newChild;
signal aux[4];
component oldProofHash = SMTHash2();
component newProofHash = SMTHash2();
component oldSwitcher = Switcher();
component newSwitcher = Switcher();
// Old side
oldSwitcher.L <== oldChild;
oldSwitcher.R <== sibling;
oldSwitcher.sel <== newlrbit;
oldProofHash.L <== oldSwitcher.outL;
oldProofHash.R <== oldSwitcher.outR;
aux[0] <== old1leaf * (st_bot + st_new1 + st_upd);
oldRoot <== aux[0] + oldProofHash.out * st_top;
// New side
aux[1] <== newChild * ( st_top + st_bot);
newSwitcher.L <== aux[1] + new1leaf*st_new1;
aux[2] <== sibling*st_top;
newSwitcher.R <== aux[2] + old1leaf*st_new1;
newSwitcher.sel <== newlrbit;
newProofHash.L <== newSwitcher.outL;
newProofHash.R <== newSwitcher.outR;
aux[3] <== newProofHash.out * (st_top + st_bot + st_new1);
newRoot <== aux[3] + new1leaf * (st_old0 + st_upd);
}