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#include "rw.h"
#include <contrib/libs/openssl/include/openssl/rand.h>
int RwGenerateKey(TRwKey* rw, int bits) {
int ok = 0;
BN_CTX* ctx = NULL;
BIGNUM *rem3 = NULL, *rem7 = NULL, *mod8 = NULL, *rem5 = NULL;
BIGNUM *nmod = NULL, *twomqexp = NULL, *twompexp = NULL, *two = NULL;
int bitsp = (bits + 1) / 2;
int bitsq = bits - bitsp;
/* make sure that all components are not null */
if ((ctx = BN_CTX_secure_new()) == NULL)
goto err;
if (!rw)
goto err;
if (!rw->N && ((rw->N = BN_new()) == NULL))
goto err;
if (!rw->P && ((rw->P = BN_new()) == NULL))
goto err;
if (!rw->Q && ((rw->Q = BN_new()) == NULL))
goto err;
if (!rw->Iqmp && ((rw->Iqmp = BN_new()) == NULL))
goto err;
if (!rw->Twomq && ((rw->Twomq = BN_new()) == NULL))
goto err;
if (!rw->Twomp && ((rw->Twomp = BN_new()) == NULL))
goto err;
if (!rw->Dq && ((rw->Dq = BN_new()) == NULL))
goto err;
if (!rw->Dp && ((rw->Dp = BN_new()) == NULL))
goto err;
BN_CTX_start(ctx);
rem3 = BN_CTX_get(ctx);
rem7 = BN_CTX_get(ctx);
rem5 = BN_CTX_get(ctx);
mod8 = BN_CTX_get(ctx);
nmod = BN_CTX_get(ctx);
twomqexp = BN_CTX_get(ctx);
twompexp = BN_CTX_get(ctx);
two = BN_CTX_get(ctx);
if (!BN_set_word(mod8, 8))
goto err;
if (!BN_set_word(rem3, 3))
goto err;
if (!BN_set_word(rem7, 7))
goto err;
if (!BN_set_word(rem5, 5))
goto err;
if (!BN_set_word(two, 2))
goto err;
/* generate p */
/* add == 8 */
/* rem == 3 */
/* safe == 0 as we don't need (p-1)/2 to be also prime */
if (!BN_generate_prime_ex(rw->P, bitsp, 0, mod8, rem3, NULL))
goto err;
/* generate q */
/* add == 8 */
/* rem == 7 */
/* safe == 0 */
if (!BN_generate_prime_ex(rw->Q, bitsq, 0, mod8, rem7, NULL))
goto err;
/* n == p*q */
if (!BN_mul(rw->N, rw->P, rw->Q, ctx))
goto err;
/* n == 5 mod 8 ? */
if (!BN_nnmod(nmod, rw->N, mod8, ctx))
goto err;
if (BN_ucmp(rem5, nmod) != 0)
goto err;
/* q^(-1) mod p */
if (!BN_mod_inverse(rw->Iqmp, rw->Q, rw->P, ctx))
goto err;
/* twomqexp = (3q-5)/8 */
if (!BN_copy(twomqexp, rw->Q))
goto err;
if (!BN_mul_word(twomqexp, 3))
goto err;
if (!BN_sub_word(twomqexp, 5))
goto err;
if (!BN_rshift(twomqexp, twomqexp, 3))
goto err;
if (!BN_mod_exp(rw->Twomq, two, twomqexp, rw->Q, ctx))
goto err;
/* twompexp = (9p-11)/8 */
if (!BN_copy(twompexp, rw->P))
goto err;
if (!BN_mul_word(twompexp, 9))
goto err;
if (!BN_sub_word(twompexp, 11))
goto err;
if (!BN_rshift(twompexp, twompexp, 3))
goto err;
if (!BN_mod_exp(rw->Twomp, two, twompexp, rw->P, ctx))
goto err;
/* dp = (p-3) / 8 */
if (!BN_copy(rw->Dp, rw->P))
goto err;
if (!BN_sub_word(rw->Dp, 3))
goto err;
if (!BN_rshift(rw->Dp, rw->Dp, 3))
goto err;
/* dq = (q+1) / 8 */
if (!BN_copy(rw->Dq, rw->Q))
goto err;
if (!BN_add_word(rw->Dq, 1))
goto err;
if (!BN_rshift(rw->Dq, rw->Dq, 3))
goto err;
ok = 1;
err:
if (ctx != NULL) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
return ok;
}
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