tibia-client/src/framework/net/rsa.cpp

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/*
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* Copyright (c) 2010-2012 OTClient <https://github.com/edubart/otclient>
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*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
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#include "rsa.h"
#include <gmp.h>
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void RSA::encrypt(char *msg, int size, const char* key)
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{
assert(size <= 128);
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mpz_t plain, c;
mpz_init2(plain, 1024);
mpz_init2(c, 1024);
mpz_t e;
mpz_init(e);
mpz_set_ui(e,65537);
mpz_t mod;
mpz_init2(mod, 1024);
mpz_set_str(mod, key, 10);
mpz_import(plain, size, 1, 1, 0, 0, msg);
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mpz_powm(c, plain, e, mod);
size_t count = (mpz_sizeinbase(c, 2) + 7)/8;
memset(msg, 0, size - count);
mpz_export(&msg[size - count], NULL, 1, 1, 0, 0, c);
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mpz_clear(c);
mpz_clear(plain);
mpz_clear(e);
mpz_clear(mod);
}
void RSA::decrypt(char *msg, int size, const char *p, const char *q, const char *d)
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{
assert(size <= 128);
mpz_t mp, mq, md, u, dp, dq, mod, c, v1, v2, u2, tmp;
mpz_init2(mp, 1024);
mpz_init2(mq, 1024);
mpz_init2(md, 1024);
mpz_init2(u, 1024);
mpz_init2(dp, 1024);
mpz_init2(dq, 1024);
mpz_init2(mod, 1024);
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mpz_init2(c, 1024);
mpz_init2(v1, 1024);
mpz_init2(v2, 1024);
mpz_init2(u2, 1024);
mpz_init2(tmp, 1024);
mpz_set_str(mp, p, 10);
mpz_set_str(mq, q, 10);
mpz_set_str(md, d, 10);
mpz_t pm1,qm1;
mpz_init2(pm1, 520);
mpz_init2(qm1, 520);
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mpz_sub_ui(pm1, mp, 1);
mpz_sub_ui(qm1, mq, 1);
mpz_invert(u, mp, mq);
mpz_mod(dp, md, pm1);
mpz_mod(dq, md, qm1);
mpz_mul(mod, mp, mq);
mpz_import(c, size, 1, 1, 0, 0, msg);
mpz_mod(tmp, c, mp);
mpz_powm(v1, tmp, dp, mp);
mpz_mod(tmp, c, mq);
mpz_powm(v2, tmp, dq, mq);
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mpz_sub(u2, v2, v1);
mpz_mul(tmp, u2, u);
mpz_mod(u2, tmp, mq);
if(mpz_cmp_si(u2, 0) < 0) {
mpz_add(tmp, u2, mq);
mpz_set(u2, tmp);
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}
mpz_mul(tmp, u2, mp);
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mpz_set_ui(c, 0);
mpz_add(c, v1, tmp);
size_t count = (mpz_sizeinbase(c, 2) + 7)/8;
memset(msg, 0, size - count);
mpz_export(&msg[size - count], NULL, 1, 1, 0, 0, c);
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mpz_clear(c);
mpz_clear(v1);
mpz_clear(v2);
mpz_clear(u2);
mpz_clear(tmp);
mpz_clear(pm1);
mpz_clear(qm1);
mpz_clear(mp);
mpz_clear(mq);
mpz_clear(md);
mpz_clear(u);
mpz_clear(dp);
mpz_clear(dq);
mpz_clear(mod);
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}