45 lines
1.2 KiB
Plaintext
45 lines
1.2 KiB
Plaintext
/*
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Copyright 2018 0KIMS association.
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This file is part of circom (Zero Knowledge Circuit Compiler).
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circom is a free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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circom is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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You should have received a copy of the GNU General Public License
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along with circom. If not, see <https://www.gnu.org/licenses/>.
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*/
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/* Xor3 function for sha256
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out = a ^ b ^ c =>
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out = a+b+c - 2*a*b - 2*a*c - 2*b*c + 4*a*b*c =>
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out = a*( 1 - 2*b - 2*c + 4*b*c ) + b + c - 2*b*c =>
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mid = b*c
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out = a*( 1 - 2*b -2*c + 4*mid ) + b + c - 2 * mid
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*/
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template Xor3(n) {
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signal input a[n];
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signal input b[n];
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signal input c[n];
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signal output out[n];
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signal mid[n];
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for (var k=0; k<n; k++) {
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mid[k] <== b[k]*c[k];
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out[k] <== a[k] * (1 -2*b[k] -2*c[k] +4*mid[k]) + b[k] + c[k] -2*mid[k];
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}
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}
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