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Adapt rsa_gen_key to deal with RSA_NO_CRT option

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This commit is contained in:
Hanno Becker 2017-08-23 06:59:15 +01:00
parent dc95c890ad
commit bee3aaeb50
1 changed files with 24 additions and 15 deletions
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39
library/rsa.c
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@ -906,7 +906,7 @@ int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
unsigned int nbits, int exponent ) unsigned int nbits, int exponent )
{ {
int ret; int ret;
mbedtls_mpi P1, Q1, H, G; mbedtls_mpi H, G;
if( f_rng == NULL || nbits < 128 || exponent < 3 ) if( f_rng == NULL || nbits < 128 || exponent < 3 )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
@ -914,8 +914,8 @@ int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
if( nbits % 2 ) if( nbits % 2 )
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
mbedtls_mpi_init( &P1 ); mbedtls_mpi_init( &Q1 ); mbedtls_mpi_init( &H );
mbedtls_mpi_init( &H ); mbedtls_mpi_init( &G ); mbedtls_mpi_init( &G );
/* /*
* find primes P and Q with Q < P so that: * find primes P and Q with Q < P so that:
@ -926,10 +926,10 @@ int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
do do
{ {
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1, 0, MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1, 0,
f_rng, p_rng ) ); f_rng, p_rng ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1, 0, MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1, 0,
f_rng, p_rng ) ); f_rng, p_rng ) );
if( mbedtls_mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 ) if( mbedtls_mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 )
continue; continue;
@ -939,34 +939,43 @@ int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx,
continue; continue;
if( mbedtls_mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 ) if( mbedtls_mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 )
mbedtls_mpi_swap( &ctx->P, &ctx->Q ); mbedtls_mpi_swap( &ctx->P, &ctx->Q );
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &P1, &ctx->P, 1 ) ); /* Temporarily replace P,Q by P-1, Q-1 */
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &Q1, &ctx->Q, 1 ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->P, &ctx->P, 1 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &H, &P1, &Q1 ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->Q, &ctx->Q, 1 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &H, &ctx->P, &ctx->Q ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->E, &H ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->E, &H ) );
} }
while( mbedtls_mpi_cmp_int( &G, 1 ) != 0 ); while( mbedtls_mpi_cmp_int( &G, 1 ) != 0 );
/* Restore P,Q */
MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->P, &ctx->P, 1 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->Q, &ctx->Q, 1 ) );
ctx->len = mbedtls_mpi_size( &ctx->N );
/* /*
* D = E^-1 mod ((P-1)*(Q-1)) * D = E^-1 mod ((P-1)*(Q-1))
* DP = D mod (P - 1) * DP = D mod (P - 1)
* DQ = D mod (Q - 1) * DQ = D mod (Q - 1)
* QP = Q^-1 mod P * QP = Q^-1 mod P
*/ */
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->D , &ctx->E, &H ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) );
ctx->len = ( mbedtls_mpi_bitlen( &ctx->N ) + 7 ) >> 3; MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->D, &ctx->E, &H ) );
#if !defined(MBEDTLS_RSA_NO_CRT)
MBEDTLS_MPI_CHK( mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D,
&ctx->DP, &ctx->DQ, &ctx->QP ) );
#endif /* MBEDTLS_RSA_NO_CRT */
/* Double-check */ /* Double-check */
MBEDTLS_MPI_CHK( mbedtls_rsa_check_privkey( ctx ) ); MBEDTLS_MPI_CHK( mbedtls_rsa_check_privkey( ctx ) );
cleanup: cleanup:
mbedtls_mpi_free( &P1 ); mbedtls_mpi_free( &Q1 ); mbedtls_mpi_free( &H ); mbedtls_mpi_free( &G ); mbedtls_mpi_free( &H );
mbedtls_mpi_free( &G );
if( ret != 0 ) if( ret != 0 )
{ {