static int ctr_rsa_key_init(ctr_rsa_context* ctx )
{
int ret;
mpi P1, Q1;
mpi_init( &P1, &Q1, NULL );
MPI_CHK( mpi_sub_int( &P1, &ctx->rsa.P, 1 ) );
MPI_CHK( mpi_sub_int( &Q1, &ctx->rsa.Q, 1 ) );
/*
* DP = D mod (P - 1)
* DQ = D mod (Q - 1)
* QP = Q^-1 mod P
*/
MPI_CHK( mpi_mod_mpi( &ctx->rsa.DP, &ctx->rsa.D, &P1 ) );
MPI_CHK( mpi_mod_mpi( &ctx->rsa.DQ, &ctx->rsa.D, &Q1 ) );
MPI_CHK( mpi_inv_mod( &ctx->rsa.QP, &ctx->rsa.Q, &ctx->rsa.P ) );
cleanup:
mpi_free(&Q1, &P1, NULL );
if( ret != 0 )
{
rsa_free( &ctx->rsa );
return( POLARSSL_ERR_RSA_KEY_GEN_FAILED | ret );
}
return( 0 );
}
/*
* Generate or update blinding values, see section 10 of:
* KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
* DSS, and other systems. In : Advances in Cryptology—CRYPTO’96. Springer
* Berlin Heidelberg, 1996. p. 104-113.
*/
static int rsa_prepare_blinding( rsa_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
{
int ret;
if( ctx->Vf.p != NULL )
{
/* We already have blinding values, just update them by squaring */
MPI_CHK( mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) );
MPI_CHK( mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) );
MPI_CHK( mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) );
MPI_CHK( mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->N ) );
return( 0 );
}
/* Unblinding value: Vf = random number */
MPI_CHK( mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) );
/* Mathematically speaking, the algorithm should check Vf
* against 0, P and Q (Vf should be relatively prime to N, and 0 < Vf < N),
* so that Vf^-1 exists.
*/
/* 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 );
}
/*
* Generate an RSA keypair
*/
int rsa_gen_key( rsa_context *ctx, int nbits, int exponent,
ulong (*rng_fn)(void *), void *rng_st )
{
int ret;
mpi P1, Q1, H, G;
mpi_init( &P1, &Q1, &H, &G, NULL );
memset( ctx, 0, sizeof( rsa_context ) );
/*
* find primes P and Q with Q < P so that:
* GCD( E, (P-1)*(Q-1) ) == 1
*/
CHK( mpi_lset( &ctx->E, exponent ) );
nbits >>= 1;
do
{
CHK( mpi_gen_prime( &ctx->P, nbits, 0, rng_fn, rng_st ) );
CHK( mpi_gen_prime( &ctx->Q, nbits, 0, rng_fn, rng_st ) );
if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 )
mpi_swap( &ctx->P, &ctx->Q );
CHK( mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) );
CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );
CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );
CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );
CHK( mpi_gcd( &G, &ctx->E, &H ) );
}
while( mpi_cmp_int( &G, 1 ) != 0 );
/*
* D = E^-1 mod ((P-1)*(Q-1))
* DP = D mod (P - 1)
* DQ = D mod (Q - 1)
* QP = Q^-1 mod P
*/
CHK( mpi_inv_mod( &ctx->D , &ctx->E, &H ) );
CHK( mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) );
CHK( mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) );
CHK( mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) );
ctx->len = ( mpi_size( &ctx->N ) + 7 ) >> 3;
cleanup:
mpi_free( &P1, &Q1, &H, &G, NULL );
if( ret != 0 )
{
rsa_free( ctx );
return( ERR_RSA_KEYGEN_FAILED | ret );
}
return( 0 );
}
/*
* Check a private RSA key
*/
int rsa_check_privkey( const rsa_context *ctx )
{
int ret;
mpi PQ, DE, P1, Q1, H, I, G, G2, L1, L2, DP, DQ, QP;
if( ( ret = rsa_check_pubkey( ctx ) ) != 0 )
return( ret );
if( !ctx->P.p || !ctx->Q.p || !ctx->D.p )
return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );
mpi_init( &PQ ); mpi_init( &DE ); mpi_init( &P1 ); mpi_init( &Q1 );
mpi_init( &H ); mpi_init( &I ); mpi_init( &G ); mpi_init( &G2 );
mpi_init( &L1 ); mpi_init( &L2 ); mpi_init( &DP ); mpi_init( &DQ );
mpi_init( &QP );
MPI_CHK( mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) );
MPI_CHK( mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) );
MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );
MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );
MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );
MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) );
MPI_CHK( mpi_gcd( &G2, &P1, &Q1 ) );
MPI_CHK( mpi_div_mpi( &L1, &L2, &H, &G2 ) );
MPI_CHK( mpi_mod_mpi( &I, &DE, &L1 ) );
MPI_CHK( mpi_mod_mpi( &DP, &ctx->D, &P1 ) );
MPI_CHK( mpi_mod_mpi( &DQ, &ctx->D, &Q1 ) );
MPI_CHK( mpi_inv_mod( &QP, &ctx->Q, &ctx->P ) );
/*
* Check for a valid PKCS1v2 private key
*/
if( mpi_cmp_mpi( &PQ, &ctx->N ) != 0 ||
mpi_cmp_mpi( &DP, &ctx->DP ) != 0 ||
mpi_cmp_mpi( &DQ, &ctx->DQ ) != 0 ||
mpi_cmp_mpi( &QP, &ctx->QP ) != 0 ||
mpi_cmp_int( &L2, 0 ) != 0 ||
mpi_cmp_int( &I, 1 ) != 0 ||
mpi_cmp_int( &G, 1 ) != 0 )
{
ret = POLARSSL_ERR_RSA_KEY_CHECK_FAILED;
}
cleanup:
mpi_free( &PQ ); mpi_free( &DE ); mpi_free( &P1 ); mpi_free( &Q1 );
mpi_free( &H ); mpi_free( &I ); mpi_free( &G ); mpi_free( &G2 );
mpi_free( &L1 ); mpi_free( &L2 ); mpi_free( &DP ); mpi_free( &DQ );
mpi_free( &QP );
if( ret == POLARSSL_ERR_RSA_KEY_CHECK_FAILED )
return( ret );
if( ret != 0 )
return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED + ret );
return( 0 );
}
/*
Generate an RSA keypair
*/
int rsa_gen_key(rsa_context *ctx, int nbits, int exponent)
{
mpi P1, Q1, H, G;
int ret;
if (ctx->f_rng == NULL || nbits < 128 || exponent < 3) {
return EST_ERR_RSA_BAD_INPUT_DATA;
}
mpi_init(&P1, &Q1, &H, &G, NULL);
/*
find primes P and Q with Q < P so that: GCD( E, (P-1)*(Q-1) ) == 1
*/
MPI_CHK(mpi_lset(&ctx->E, exponent));
do {
MPI_CHK(mpi_gen_prime(&ctx->P, (nbits + 1) >> 1, 0, ctx->f_rng, ctx->p_rng));
MPI_CHK(mpi_gen_prime(&ctx->Q, (nbits + 1) >> 1, 0, ctx->f_rng, ctx->p_rng));
if (mpi_cmp_mpi(&ctx->P, &ctx->Q) < 0) {
mpi_swap(&ctx->P, &ctx->Q);
}
if (mpi_cmp_mpi(&ctx->P, &ctx->Q) == 0) {
continue;
}
MPI_CHK(mpi_mul_mpi(&ctx->N, &ctx->P, &ctx->Q));
if (mpi_msb(&ctx->N) != nbits) {
continue;
}
MPI_CHK(mpi_sub_int(&P1, &ctx->P, 1));
MPI_CHK(mpi_sub_int(&Q1, &ctx->Q, 1));
MPI_CHK(mpi_mul_mpi(&H, &P1, &Q1));
MPI_CHK(mpi_gcd(&G, &ctx->E, &H));
} while (mpi_cmp_int(&G, 1) != 0);
/*
D = E^-1 mod ((P-1)*(Q-1))
DP = D mod (P - 1)
DQ = D mod (Q - 1)
QP = Q^-1 mod P
*/
MPI_CHK(mpi_inv_mod(&ctx->D, &ctx->E, &H));
MPI_CHK(mpi_mod_mpi(&ctx->DP, &ctx->D, &P1));
MPI_CHK(mpi_mod_mpi(&ctx->DQ, &ctx->D, &Q1));
MPI_CHK(mpi_inv_mod(&ctx->QP, &ctx->Q, &ctx->P));
ctx->len = (mpi_msb(&ctx->N) + 7) >> 3;
cleanup:
mpi_free(&G, &H, &Q1, &P1, NULL);
if (ret != 0) {
rsa_free(ctx);
return EST_ERR_RSA_KEY_GEN_FAILED | ret;
}
return 0;
}
int
rsa_decrypt (const uint8_t *input, uint8_t *output, int msg_len,
struct key_data *kd)
{
mpi P1, Q1, H;
int r;
int output_len;
DEBUG_INFO ("RSA decrypt:");
DEBUG_WORD ((uint32_t)&output_len);
mpi_init (&P1, &Q1, &H, NULL);
rsa_init (&rsa_ctx, RSA_PKCS_V15, 0);
rsa_ctx.len = msg_len;
DEBUG_WORD (msg_len);
mpi_lset (&rsa_ctx.E, 0x10001);
mpi_read_binary (&rsa_ctx.P, &kd->data[0], KEY_CONTENT_LEN / 2);
mpi_read_binary (&rsa_ctx.Q, &kd->data[KEY_CONTENT_LEN/2],
KEY_CONTENT_LEN / 2);
#if 0 /* Using CRT, we don't use N */
mpi_mul_mpi (&rsa_ctx.N, &rsa_ctx.P, &rsa_ctx.Q);
#endif
mpi_sub_int (&P1, &rsa_ctx.P, 1);
mpi_sub_int (&Q1, &rsa_ctx.Q, 1);
mpi_mul_mpi (&H, &P1, &Q1);
mpi_inv_mod (&rsa_ctx.D , &rsa_ctx.E, &H);
mpi_mod_mpi (&rsa_ctx.DP, &rsa_ctx.D, &P1);
mpi_mod_mpi (&rsa_ctx.DQ, &rsa_ctx.D, &Q1);
mpi_inv_mod (&rsa_ctx.QP, &rsa_ctx.Q, &rsa_ctx.P);
mpi_free (&P1, &Q1, &H, NULL);
DEBUG_INFO ("RSA decrypt ...");
r = rsa_pkcs1_decrypt (&rsa_ctx, RSA_PRIVATE, &output_len,
input, output, MAX_RES_APDU_DATA_SIZE);
rsa_free (&rsa_ctx);
if (r < 0)
{
DEBUG_INFO ("fail:");
DEBUG_SHORT (r);
return r;
}
else
{
res_APDU_size = output_len;
DEBUG_INFO ("done.\r\n");
GPG_SUCCESS ();
return 0;
}
}
/*
* Check a private RSA key
*/
int rsa_check_privkey( rsa_context *ctx )
{
int ret;
mpi PQ, DE, P1, Q1, H, I, G;
if( ( ret = rsa_check_pubkey( ctx ) ) != 0 )
return( ret );
if( !ctx->P.p || !ctx->Q.p || !ctx->D.p )
return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );
mpi_init( &PQ, &DE, &P1, &Q1, &H, &I, &G, NULL );
MPI_CHK( mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) );
MPI_CHK( mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) );
MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );
MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );
MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );
MPI_CHK( mpi_mod_mpi( &I, &DE, &H ) );
MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) );
if( mpi_cmp_mpi( &PQ, &ctx->N ) == 0 &&
mpi_cmp_int( &I, 1 ) == 0 &&
mpi_cmp_int( &G, 1 ) == 0 )
{
mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, NULL );
return( 0 );
}
cleanup:
mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, NULL );
return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED | ret );
}
/*
* Generate or update blinding values, see section 10 of:
* KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
* DSS, and other systems. In : Advances in Cryptology—CRYPTO’96. Springer
* Berlin Heidelberg, 1996. p. 104-113.
*/
static int rsa_prepare_blinding( rsa_context *ctx, mpi *Vi, mpi *Vf,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
{
int ret, count = 0;
#if defined(POLARSSL_THREADING_C)
polarssl_mutex_lock( &ctx->mutex );
#endif
if( ctx->Vf.p != NULL )
{
/* We already have blinding values, just update them by squaring */
MPI_CHK( mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) );
MPI_CHK( mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) );
MPI_CHK( mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) );
MPI_CHK( mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->N ) );
goto done;
}
/* Unblinding value: Vf = random number, invertible mod N */
do {
if( count++ > 10 )
return( POLARSSL_ERR_RSA_RNG_FAILED );
MPI_CHK( mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) );
MPI_CHK( mpi_gcd( &ctx->Vi, &ctx->Vf, &ctx->N ) );
} while( mpi_cmp_int( &ctx->Vi, 1 ) != 0 );
/* 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 ) );
done:
if( Vi != &ctx->Vi )
{
MPI_CHK( mpi_copy( Vi, &ctx->Vi ) );
MPI_CHK( mpi_copy( Vf, &ctx->Vf ) );
}
cleanup:
#if defined(POLARSSL_THREADING_C)
polarssl_mutex_unlock( &ctx->mutex );
#endif
return( ret );
}
int
rsa_sign (const uint8_t *raw_message, uint8_t *output, int msg_len,
struct key_data *kd)
{
mpi P1, Q1, H;
int r;
unsigned char temp[RSA_SIGNATURE_LENGTH];
mpi_init (&P1, &Q1, &H, NULL);
rsa_init (&rsa_ctx, RSA_PKCS_V15, 0);
rsa_ctx.len = KEY_CONTENT_LEN;
mpi_lset (&rsa_ctx.E, 0x10001);
mpi_read_binary (&rsa_ctx.P, &kd->data[0], rsa_ctx.len / 2);
mpi_read_binary (&rsa_ctx.Q, &kd->data[KEY_CONTENT_LEN/2], rsa_ctx.len / 2);
#if 0 /* Using CRT, we don't use N */
mpi_mul_mpi (&rsa_ctx.N, &rsa_ctx.P, &rsa_ctx.Q);
#endif
mpi_sub_int (&P1, &rsa_ctx.P, 1);
mpi_sub_int (&Q1, &rsa_ctx.Q, 1);
mpi_mul_mpi (&H, &P1, &Q1);
mpi_inv_mod (&rsa_ctx.D , &rsa_ctx.E, &H);
mpi_mod_mpi (&rsa_ctx.DP, &rsa_ctx.D, &P1);
mpi_mod_mpi (&rsa_ctx.DQ, &rsa_ctx.D, &Q1);
mpi_inv_mod (&rsa_ctx.QP, &rsa_ctx.Q, &rsa_ctx.P);
mpi_free (&P1, &Q1, &H, NULL);
DEBUG_INFO ("RSA sign...");
r = rsa_pkcs1_sign (&rsa_ctx, RSA_PRIVATE, SIG_RSA_RAW,
msg_len, raw_message, temp);
memcpy (output, temp, RSA_SIGNATURE_LENGTH);
rsa_free (&rsa_ctx);
if (r < 0)
{
DEBUG_INFO ("fail:");
DEBUG_SHORT (r);
return r;
}
else
{
res_APDU_size = RSA_SIGNATURE_LENGTH;
DEBUG_INFO ("done.\r\n");
GPG_SUCCESS ();
return 0;
}
}
/*
* Do an RSA private key operation
*/
int rsa_private( rsa_context *ctx,
unsigned char *input,
unsigned char *output )
{
int ret, olen;
mpi T, T1, T2;
//printf("RSA private key operation start\n");
mpi_init( &T, &T1, &T2, NULL );
MPI_CHK( mpi_read_binary( &T, input, ctx->len ) );
if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
{
mpi_free( &T, NULL );
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
}
#if 0
MPI_CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) );
#else
/*
* faster decryption using the CRT
*
* T1 = input ^ dP mod P
* T2 = input ^ dQ mod Q
*/
MPI_CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) );
MPI_CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) );
/*
* T = (T1 - T2) * (Q^-1 mod P) mod P
*/
MPI_CHK( mpi_sub_mpi( &T, &T1, &T2 ) );
MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) );
MPI_CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) );
/*
* output = T2 + T * Q
*/
MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) );
MPI_CHK( mpi_add_mpi( &T, &T2, &T1 ) );
#endif
olen = ctx->len;
MPI_CHK( mpi_write_binary( &T, output, olen ) );
cleanup:
mpi_free( &T, &T1, &T2, NULL );
//printf("RSA private key operation end\n");
if( ret != 0 )
return( POLARSSL_ERR_RSA_PRIVATE_FAILED | ret );
return( 0 );
}
/*
* Perform an RSA private key operation
*/
int rsa_private( rsa_context *ctx,
unsigned char *input, int ilen,
unsigned char *output, int *olen )
{
int ret;
mpi T, T1, T2;
//if( ilen != ctx->len || olen != ctx->len )
// return( ERR_RSA_BAD_INPUT_DATA );
mpi_init( &T, &T1, &T2, NULL );
CHK( mpi_import( &T, input, ilen ) );
if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
{
mpi_free( &T, NULL );
return( ERR_RSA_BAD_INPUT_DATA );
}
#if 0
CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) );
#else
/*
* faster decryption using the CRT
*
* T1 = input ^ dP mod P
* T2 = input ^ dQ mod Q
*/
CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) );
CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) );
/*
* T = (T1 - T2) * (Q^-1 mod P) mod P
*/
CHK( mpi_sub_mpi( &T, &T1, &T2 ) );
CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) );
CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) );
/*
* output = T2 + T * Q
*/
CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) );
CHK( mpi_add_mpi( &T, &T2, &T1 ) );
#endif
CHK( mpi_export( &T, output, olen ) );
cleanup:
mpi_free( &T, &T1, &T2, NULL );
if( ret != 0 )
return( ERR_RSA_PRIVATE_FAILED | ret );
return( 0 );
}
/*
Do an RSA private key operation
*/
int rsa_private(rsa_context *ctx, uchar *input, uchar *output)
{
int ret, olen;
mpi T, T1, T2;
mpi_init(&T, &T1, &T2, NULL);
MPI_CHK(mpi_read_binary(&T, input, ctx->len));
if (mpi_cmp_mpi(&T, &ctx->N) >= 0) {
mpi_free(&T, NULL);
return EST_ERR_RSA_BAD_INPUT_DATA;
}
// MOB - why ?
#if 0
MPI_CHK(mpi_exp_mod(&T, &T, &ctx->D, &ctx->N, &ctx->RN));
#else
/*
faster decryption using the CRT
T1 = input ^ dP mod P
T2 = input ^ dQ mod Q
*/
MPI_CHK(mpi_exp_mod(&T1, &T, &ctx->DP, &ctx->P, &ctx->RP));
MPI_CHK(mpi_exp_mod(&T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ));
/*
T = (T1 - T2) * (Q^-1 mod P) mod P
*/
MPI_CHK(mpi_sub_mpi(&T, &T1, &T2));
MPI_CHK(mpi_mul_mpi(&T1, &T, &ctx->QP));
MPI_CHK(mpi_mod_mpi(&T, &T1, &ctx->P));
/*
output = T2 + T * Q
*/
MPI_CHK(mpi_mul_mpi(&T1, &T, &ctx->Q));
MPI_CHK(mpi_add_mpi(&T, &T2, &T1));
#endif
olen = ctx->len;
MPI_CHK(mpi_write_binary(&T, output, olen));
cleanup:
mpi_free(&T, &T1, &T2, NULL);
if (ret != 0)
return EST_ERR_RSA_PRIVATE_FAILED | ret;
return 0;
}
/*
* Check a private RSA key
*/
int rsa_check_privkey( const rsa_context *ctx )
{
int ret;
mpi PQ, DE, P1, Q1, H, I, G, G2, L1, L2;
if( ( ret = rsa_check_pubkey( ctx ) ) != 0 )
return( ret );
if( !ctx->P.p || !ctx->Q.p || !ctx->D.p )
return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED );
mpi_init( &PQ, &DE, &P1, &Q1, &H, &I, &G, &G2, &L1, &L2, NULL );
MPI_CHK( mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) );
MPI_CHK( mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) );
MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );
MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );
MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );
MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) );
MPI_CHK( mpi_gcd( &G2, &P1, &Q1 ) );
MPI_CHK( mpi_div_mpi( &L1, &L2, &H, &G2 ) );
MPI_CHK( mpi_mod_mpi( &I, &DE, &L1 ) );
/*
* Check for a valid PKCS1v2 private key
*/
if( mpi_cmp_mpi( &PQ, &ctx->N ) == 0 &&
mpi_cmp_int( &L2, 0 ) == 0 &&
mpi_cmp_int( &I, 1 ) == 0 &&
mpi_cmp_int( &G, 1 ) == 0 )
{
mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, &G2, &L1, &L2, NULL );
return( 0 );
}
cleanup:
mpi_free( &G, &I, &H, &Q1, &P1, &DE, &PQ, &G2, &L1, &L2, NULL );
return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED | ret );
}
/*
* Generate an RSA keypair
*/
int rsa_gen_key( rsa_context *ctx,
int (*f_rng)(void *),
void *p_rng,
int nbits, int exponent )
{
int ret;
mpi P1, Q1, H, G;
if( f_rng == NULL || nbits < 128 || exponent < 3 )
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
mpi_init( &P1, &Q1, &H, &G, NULL );
/*
* find primes P and Q with Q < P so that:
* GCD( E, (P-1)*(Q-1) ) == 1
*/
MPI_CHK( mpi_lset( &ctx->E, exponent ) );
do
{
MPI_CHK( mpi_gen_prime( &ctx->P, ( nbits + 1 ) >> 1, 0,
f_rng, p_rng ) );
MPI_CHK( mpi_gen_prime( &ctx->Q, ( nbits + 1 ) >> 1, 0,
f_rng, p_rng ) );
if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 )
mpi_swap( &ctx->P, &ctx->Q );
if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 )
continue;
MPI_CHK( mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) );
if( mpi_msb( &ctx->N ) != nbits )
continue;
MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) );
MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) );
MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) );
MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) );
}
while( mpi_cmp_int( &G, 1 ) != 0 );
/*
* D = E^-1 mod ((P-1)*(Q-1))
* DP = D mod (P - 1)
* DQ = D mod (Q - 1)
* QP = Q^-1 mod P
*/
MPI_CHK( mpi_inv_mod( &ctx->D , &ctx->E, &H ) );
MPI_CHK( mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) );
MPI_CHK( mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) );
MPI_CHK( mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) );
ctx->len = ( mpi_msb( &ctx->N ) + 7 ) >> 3;
cleanup:
mpi_free( &G, &H, &Q1, &P1, NULL );
if( ret != 0 )
{
rsa_free( ctx );
return( POLARSSL_ERR_RSA_KEY_GEN_FAILED | ret );
}
return( 0 );
}
/*
* Do an RSA private key operation
*/
int rsa_private( rsa_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng,
const unsigned char *input,
unsigned char *output )
{
int ret;
size_t olen;
mpi T, T1, T2;
mpi_init( &T ); mpi_init( &T1 ); mpi_init( &T2 );
MPI_CHK( mpi_read_binary( &T, input, ctx->len ) );
if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
{
mpi_free( &T );
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
}
#if defined(POLARSSL_RSA_NO_CRT)
((void) f_rng);
((void) p_rng);
MPI_CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) );
#else
if( f_rng != NULL )
{
/*
* Blinding
* T = T * Vi mod N
*/
MPI_CHK( rsa_prepare_blinding( ctx, f_rng, p_rng ) );
MPI_CHK( mpi_mul_mpi( &T, &T, &ctx->Vi ) );
MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) );
}
/*
* faster decryption using the CRT
*
* T1 = input ^ dP mod P
* T2 = input ^ dQ mod Q
*/
MPI_CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) );
MPI_CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) );
/*
* T = (T1 - T2) * (Q^-1 mod P) mod P
*/
MPI_CHK( mpi_sub_mpi( &T, &T1, &T2 ) );
MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) );
MPI_CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) );
/*
* output = T2 + T * Q
*/
MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) );
MPI_CHK( mpi_add_mpi( &T, &T2, &T1 ) );
if( f_rng != NULL )
{
/*
* Unblind
* T = T * Vf mod N
*/
MPI_CHK( mpi_mul_mpi( &T, &T, &ctx->Vf ) );
MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) );
}
#endif
olen = ctx->len;
MPI_CHK( mpi_write_binary( &T, output, olen ) );
cleanup:
mpi_free( &T ); mpi_free( &T1 ); mpi_free( &T2 );
if( ret != 0 )
return( POLARSSL_ERR_RSA_PRIVATE_FAILED + ret );
return( 0 );
}
/*
* Do an RSA private key operation
*/
int rsa_private( rsa_context *ctx,
int (*f_rng)(void *, unsigned char *, size_t),
void *p_rng,
const unsigned char *input,
unsigned char *output )
{
int ret;
size_t olen;
mpi T, T1, T2;
#if !defined(POLARSSL_RSA_NO_CRT)
mpi *Vi, *Vf;
/*
* When using the Chinese Remainder Theorem, we use blinding values.
* Without threading, we just read them directly from the context,
* otherwise we make a local copy in order to reduce locking contention.
*/
#if defined(POLARSSL_THREADING_C)
mpi Vi_copy, Vf_copy;
mpi_init( &Vi_copy ); mpi_init( &Vf_copy );
Vi = &Vi_copy;
Vf = &Vf_copy;
#else
Vi = &ctx->Vi;
Vf = &ctx->Vf;
#endif
#endif /* !POLARSSL_RSA_NO_CRT */
mpi_init( &T ); mpi_init( &T1 ); mpi_init( &T2 );
MPI_CHK( mpi_read_binary( &T, input, ctx->len ) );
if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 )
{
mpi_free( &T );
return( POLARSSL_ERR_RSA_BAD_INPUT_DATA );
}
#if defined(POLARSSL_RSA_NO_CRT)
((void) f_rng);
((void) p_rng);
MPI_CHK( mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) );
#else
if( f_rng != NULL )
{
/*
* Blinding
* T = T * Vi mod N
*/
MPI_CHK( rsa_prepare_blinding( ctx, Vi, Vf, f_rng, p_rng ) );
MPI_CHK( mpi_mul_mpi( &T, &T, Vi ) );
MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) );
}
/*
* faster decryption using the CRT
*
* T1 = input ^ dP mod P
* T2 = input ^ dQ mod Q
*/
MPI_CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) );
MPI_CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) );
/*
* T = (T1 - T2) * (Q^-1 mod P) mod P
*/
MPI_CHK( mpi_sub_mpi( &T, &T1, &T2 ) );
MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) );
MPI_CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) );
/*
* T = T2 + T * Q
*/
MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) );
MPI_CHK( mpi_add_mpi( &T, &T2, &T1 ) );
if( f_rng != NULL )
{
/*
* Unblind
* T = T * Vf mod N
*/
MPI_CHK( mpi_mul_mpi( &T, &T, Vf ) );
MPI_CHK( mpi_mod_mpi( &T, &T, &ctx->N ) );
}
#endif /* POLARSSL_RSA_NO_CRT */
olen = ctx->len;
MPI_CHK( mpi_write_binary( &T, output, olen ) );
cleanup:
mpi_free( &T ); mpi_free( &T1 ); mpi_free( &T2 );
#if !defined(POLARSSL_RSA_NO_CRT) && defined(POLARSSL_THREADING_C)
mpi_free( &Vi_copy ); mpi_free( &Vf_copy );
#endif
if( ret != 0 )
return( POLARSSL_ERR_RSA_PRIVATE_FAILED + ret );
return( 0 );
}
