Commit ea53a55c authored by Manuel Pégourié-Gonnard's avatar Manuel Pégourié-Gonnard
Browse files

Refactor to prepare for RSA blinding optimisation

parent 032c34e2
...@@ -89,6 +89,11 @@ typedef struct ...@@ -89,6 +89,11 @@ typedef struct
mpi RP; /*!< cached R^2 mod P */ mpi RP; /*!< cached R^2 mod P */
mpi RQ; /*!< cached R^2 mod Q */ mpi RQ; /*!< cached R^2 mod Q */
#if !defined(POLARSSL_RSA_NO_CRT)
mpi Vi; /*!< cached blinding value */
mpi Vf; /*!< cached un-blinding value */
#endif
int padding; /*!< RSA_PKCS_V15 for 1.5 padding and int padding; /*!< RSA_PKCS_V15 for 1.5 padding and
RSA_PKCS_v21 for OAEP/PSS */ RSA_PKCS_v21 for OAEP/PSS */
int hash_id; /*!< Hash identifier of md_type_t as int hash_id; /*!< Hash identifier of md_type_t as
......
...@@ -253,6 +253,27 @@ cleanup: ...@@ -253,6 +253,27 @@ cleanup:
return( 0 ); return( 0 );
} }
#if !defined(POLARSSL_RSA_NO_CRT)
/*
* Generate blinding values
*/
static int rsa_prepare_blinding( rsa_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
{
int ret;
/* Unblinding value: Vf = random number */
MPI_CHK( mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) );
/* Blinding value: Vi = Vf^(-e) mod N */
MPI_CHK( mpi_inv_mod( &ctx->Vi, &ctx->Vf, &ctx->N ) );
MPI_CHK( mpi_exp_mod( &ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN ) );
cleanup:
return( ret );
}
#endif
/* /*
* Do an RSA private key operation * Do an RSA private key operation
*/ */
...@@ -265,11 +286,8 @@ int rsa_private( rsa_context *ctx, ...@@ -265,11 +286,8 @@ int rsa_private( rsa_context *ctx,
int ret; int ret;
size_t olen; size_t olen;
mpi T, T1, T2; mpi T, T1, T2;
mpi A, X;
mpi_init( &T ); mpi_init( &T1 ); mpi_init( &T2 ); mpi_init( &T ); mpi_init( &T1 ); mpi_init( &T2 );
mpi_init( &A ); mpi_init( &X );
MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); MPI_CHK( mpi_read_binary( &T, input, ctx->len ) );
if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
...@@ -284,14 +302,12 @@ int rsa_private( rsa_context *ctx, ...@@ -284,14 +302,12 @@ int rsa_private( rsa_context *ctx,
if( f_rng != NULL ) if( f_rng != NULL )
{ {
/* /*
* RSA Blinding * Blinding
* A = rnd MPI * T = T * Vi mod N
* T = A^E * T mod N
*/ */
MPI_CHK( mpi_fill_random( &A, ctx->len - 1, f_rng, p_rng ) ); MPI_CHK( rsa_prepare_blinding( ctx, f_rng, p_rng ) );
MPI_CHK( mpi_exp_mod( &X, &A, &ctx->E, &ctx->N, NULL ) ); MPI_CHK( mpi_mul_mpi( &T, &T, &ctx->Vi ) );
MPI_CHK( mpi_mul_mpi( &X, &X, &T ) ); MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) );
MPI_CHK( mpi_mod_mpi( &T, &X, &ctx->N ) );
} }
/* /*
...@@ -320,10 +336,9 @@ int rsa_private( rsa_context *ctx, ...@@ -320,10 +336,9 @@ int rsa_private( rsa_context *ctx,
{ {
/* /*
* Unblind * Unblind
* T = T / A mod N * T = T * Vf mod N
*/ */
MPI_CHK( mpi_inv_mod( &A, &A, &ctx->N ) ); MPI_CHK( mpi_mul_mpi( &T, &T, &ctx->Vf ) );
MPI_CHK( mpi_mul_mpi( &T, &T, &A ) );
MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) ); MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) );
} }
#endif #endif
...@@ -334,7 +349,6 @@ int rsa_private( rsa_context *ctx, ...@@ -334,7 +349,6 @@ int rsa_private( rsa_context *ctx,
cleanup: cleanup:
mpi_free( &T ); mpi_free( &T1 ); mpi_free( &T2 ); mpi_free( &T ); mpi_free( &T1 ); mpi_free( &T2 );
mpi_free( &A ); mpi_free( &X );
if( ret != 0 ) if( ret != 0 )
return( POLARSSL_ERR_RSA_PRIVATE_FAILED + ret ); return( POLARSSL_ERR_RSA_PRIVATE_FAILED + ret );
...@@ -1280,6 +1294,9 @@ int rsa_copy( rsa_context *dst, const rsa_context *src ) ...@@ -1280,6 +1294,9 @@ int rsa_copy( rsa_context *dst, const rsa_context *src )
MPI_CHK( mpi_copy( &dst->RP, &src->RP ) ); MPI_CHK( mpi_copy( &dst->RP, &src->RP ) );
MPI_CHK( mpi_copy( &dst->RQ, &src->RQ ) ); MPI_CHK( mpi_copy( &dst->RQ, &src->RQ ) );
MPI_CHK( mpi_copy( &dst->Vi, &src->Vi ) );
MPI_CHK( mpi_copy( &dst->Vf, &src->Vf ) );
dst->padding = src->padding; dst->padding = src->padding;
dst->hash_id = src->padding; dst->hash_id = src->padding;
...@@ -1295,6 +1312,7 @@ cleanup: ...@@ -1295,6 +1312,7 @@ cleanup:
*/ */
void rsa_free( rsa_context *ctx ) void rsa_free( rsa_context *ctx )
{ {
mpi_free( &ctx->Vi ); mpi_free( &ctx->Vf );
mpi_free( &ctx->RQ ); mpi_free( &ctx->RP ); mpi_free( &ctx->RN ); mpi_free( &ctx->RQ ); mpi_free( &ctx->RP ); mpi_free( &ctx->RN );
mpi_free( &ctx->QP ); mpi_free( &ctx->DQ ); mpi_free( &ctx->DP ); mpi_free( &ctx->QP ); mpi_free( &ctx->DQ ); mpi_free( &ctx->DP );
mpi_free( &ctx->Q ); mpi_free( &ctx->P ); mpi_free( &ctx->D ); mpi_free( &ctx->Q ); mpi_free( &ctx->P ); mpi_free( &ctx->D );
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment