105 lines
2.5 KiB
C++
105 lines
2.5 KiB
C++
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/*
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* This file is part of Codecrypt.
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*
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* Copyright (C) 2013-2016 Mirek Kratochvil <exa.exa@gmail.com>
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*
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* Codecrypt is free software: you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or (at
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* your option) any later version.
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*
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* Codecrypt 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 or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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* License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with Codecrypt. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _ccr_mce_qd_h_
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#define _ccr_mce_qd_h_
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#include <vector>
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#include "bvector.h"
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#include "gf2m.h"
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#include "matrix.h"
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#include "permutation.h"
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#include "polynomial.h"
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#include "prng.h"
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#include "sencode.h"
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#include "types.h"
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/*
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* compact Quasi-dyadic McEliece
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* according to Misoczki, Barreto, Compact McEliece Keys from Goppa Codes.
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*
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* Needs plaintext conversion. Unfortunately broken by an algebraic attack, do
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* not use this.
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*/
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namespace mce_qd
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{
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class privkey
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{
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public:
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std::vector<uint> essence;
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gf2m fld; //we fix q=2^fld.m=fld.n, n=q/2
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uint T; //the QD's t parameter is 2^T.
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permutation block_perm; //order of blocks
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std::vector<uint> block_perms; //dyadic permutations of blocks
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permutation hperm; //block permutation of H block used to get G
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//derivable stuff
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//pre-permuted positions of support rows and support content
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std::vector<uint> support_pos, permuted_support;
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//generating polynomial
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polynomial g;
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int decrypt (const bvector&, bvector&);
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int decrypt (const bvector&, bvector&, bvector&);
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int prepare();
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uint cipher_size() {
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return (1 << T) * hperm.size();
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}
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uint plain_size() {
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return (1 << T) * (hperm.size() - fld.m);
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}
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uint error_count() {
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return 1 << T;
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}
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sencode* serialize();
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bool unserialize (sencode*);
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};
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class pubkey
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{
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public:
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uint T;
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matrix qd_sigs;
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int encrypt (const bvector&, bvector&, prng&);
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int encrypt (const bvector&, bvector&, const bvector&);
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uint cipher_size() {
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return plain_size() + qd_sigs[0].size();
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}
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uint plain_size() {
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return (1 << T) * qd_sigs.size();
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}
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uint error_count() {
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return 1 << T;
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}
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sencode* serialize();
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bool unserialize (sencode*);
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};
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int generate (pubkey&, privkey&, prng&, uint m, uint T, uint b, uint bd);
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}
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#endif
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