/*
* 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 );
}
void test_prime_num_gen()
{
mpi p;
mpi_init(&p);
clock_t start, end;
float diff;
srand(time(0));
for (size_t i = 256; i <= 2048; i <<= 1)
{
start = clock();
mpi_gen_prime(&p, i, 0, myrand, NULL);
end = clock();
diff = ((float)(end - start)) / CLOCKS_PER_SEC;
printf("%d-bit prime number generation time: %f seconds\n", i, diff);
}
mpi_free(&p);
}
int main( int argc, char *argv[] )
{
int ret = 1;
mpi G, P, Q;
entropy_context entropy;
ctr_drbg_context ctr_drbg;
const char *pers = "dh_genprime";
FILE *fout;
((void) argc);
((void) argv);
mpi_init( &G ); mpi_init( &P ); mpi_init( &Q );
entropy_init( &entropy );
if( ( ret = mpi_read_string( &G, 10, GENERATOR ) ) != 0 )
{
polarssl_printf( " failed\n ! mpi_read_string returned %d\n", ret );
goto exit;
}
polarssl_printf( "\nWARNING: You should not generate and use your own DHM primes\n" );
polarssl_printf( " unless you are very certain of what you are doing!\n" );
polarssl_printf( " Failing to follow this instruction may result in\n" );
polarssl_printf( " weak security for your connections! Use the\n" );
polarssl_printf( " predefined DHM parameters from dhm.h instead!\n\n" );
polarssl_printf( "============================================================\n\n" );
polarssl_printf( " ! Generating large primes may take minutes!\n" );
polarssl_printf( "\n . Seeding the random number generator..." );
fflush( stdout );
if( ( ret = ctr_drbg_init( &ctr_drbg, entropy_func, &entropy,
(const unsigned char *) pers,
strlen( pers ) ) ) != 0 )
{
polarssl_printf( " failed\n ! ctr_drbg_init returned %d\n", ret );
goto exit;
}
polarssl_printf( " ok\n . Generating the modulus, please wait..." );
fflush( stdout );
/*
* This can take a long time...
*/
if( ( ret = mpi_gen_prime( &P, DH_P_SIZE, 1,
ctr_drbg_random, &ctr_drbg ) ) != 0 )
{
polarssl_printf( " failed\n ! mpi_gen_prime returned %d\n\n", ret );
goto exit;
}
polarssl_printf( " ok\n . Verifying that Q = (P-1)/2 is prime..." );
fflush( stdout );
if( ( ret = mpi_sub_int( &Q, &P, 1 ) ) != 0 )
{
polarssl_printf( " failed\n ! mpi_sub_int returned %d\n\n", ret );
goto exit;
}
if( ( ret = mpi_div_int( &Q, NULL, &Q, 2 ) ) != 0 )
{
polarssl_printf( " failed\n ! mpi_div_int returned %d\n\n", ret );
goto exit;
}
if( ( ret = mpi_is_prime( &Q, ctr_drbg_random, &ctr_drbg ) ) != 0 )
{
polarssl_printf( " failed\n ! mpi_is_prime returned %d\n\n", ret );
goto exit;
}
polarssl_printf( " ok\n . Exporting the value in dh_prime.txt..." );
fflush( stdout );
if( ( fout = fopen( "dh_prime.txt", "wb+" ) ) == NULL )
{
ret = 1;
polarssl_printf( " failed\n ! Could not create dh_prime.txt\n\n" );
goto exit;
}
if( ( ret = mpi_write_file( "P = ", &P, 16, fout ) != 0 ) ||
( ret = mpi_write_file( "G = ", &G, 16, fout ) != 0 ) )
{
polarssl_printf( " failed\n ! mpi_write_file returned %d\n\n", ret );
goto exit;
}
polarssl_printf( " ok\n\n" );
fclose( fout );
exit:
mpi_free( &G ); mpi_free( &P ); mpi_free( &Q );
ctr_drbg_free( &ctr_drbg );
entropy_free( &entropy );
#if defined(_WIN32)
polarssl_printf( " Press Enter to exit this program.\n" );
fflush( stdout ); getchar();
#endif
return( ret );
}
int main( void )
{
int ret = 1;
#if defined(XYSSL_GENPRIME)
mpi G, P, Q;
havege_state hs;
FILE *fout;
mpi_init( &G, &P, &Q, NULL );
mpi_read_string( &G, 10, GENERATOR );
printf( "\n . Seeding the random number generator..." );
fflush( stdout );
havege_init( &hs );
printf( " ok\n . Generating the modulus, please wait..." );
fflush( stdout );
/*
* This can take a long time...
*/
if( ( ret = mpi_gen_prime( &P, DH_P_SIZE, 1,
havege_rand, &hs ) ) != 0 )
{
printf( " failed\n ! mpi_gen_prime returned %d\n\n", ret );
goto exit;
}
printf( " ok\n . Verifying that Q = (P-1)/2 is prime..." );
fflush( stdout );
if( ( ret = mpi_sub_int( &Q, &P, 1 ) ) != 0 )
{
printf( " failed\n ! mpi_sub_int returned %d\n\n", ret );
goto exit;
}
if( ( ret = mpi_div_int( &Q, NULL, &Q, 2 ) ) != 0 )
{
printf( " failed\n ! mpi_div_int returned %d\n\n", ret );
goto exit;
}
if( ( ret = mpi_is_prime( &Q, havege_rand, &hs ) ) != 0 )
{
printf( " failed\n ! mpi_is_prime returned %d\n\n", ret );
goto exit;
}
printf( " ok\n . Exporting the value in dh_prime.txt..." );
fflush( stdout );
if( ( fout = fopen( "dh_prime.txt", "wb+" ) ) == NULL )
{
ret = 1;
printf( " failed\n ! Could not create dh_prime.txt\n\n" );
goto exit;
}
if( ( ret = mpi_write_file( "P = ", &P, 16, fout ) != 0 ) ||
( ret = mpi_write_file( "G = ", &G, 16, fout ) != 0 ) )
{
printf( " failed\n ! mpi_write_file returned %d\n\n", ret );
goto exit;
}
printf( " ok\n\n" );
fclose( fout );
exit:
mpi_free( &Q, &P, &G, NULL );
#else
printf( "\n ! Prime-number generation is not available.\n\n" );
#endif
#ifdef WIN32
printf( " Press Enter to exit this program.\n" );
fflush( stdout ); getchar();
#endif
return( ret );
}
