static int rsa_decrypt_wrap( void *ctx, const unsigned char *input, size_t ilen, unsigned char *output, size_t *olen, size_t osize, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) { if( ilen != ((mbedtls_rsa_context *) ctx)->len ) return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); return( mbedtls_rsa_pkcs1_decrypt( (mbedtls_rsa_context *) ctx, f_rng, p_rng, MBEDTLS_RSA_PRIVATE, olen, input, output, osize ) ); }
int decipher_aes_credentials(const unsigned char *private_key, const unsigned char *ciphertext, unsigned char *aes_credentials) { rsa_context rsa; init_rsa_context_with_private_key(&rsa, private_key); #ifdef USE_MBEDTLS size_t len = 128; int ret = mbedtls_rsa_pkcs1_decrypt(&rsa, mbedtls_default_rng, nullptr, MBEDTLS_RSA_PRIVATE, &len, ciphertext, aes_credentials, 40); #else # if PLATFORM_ID == 6 || PLATFORM_ID == 8 int32_t len = 128; # else int len = 128; # endif int ret = rsa_pkcs1_decrypt(&rsa, RSA_PRIVATE, &len, ciphertext, aes_credentials, 40); #endif rsa_free(&rsa); return ret; }
int main( int argc, char *argv[] ) { FILE *f; int ret, c; size_t i; mbedtls_rsa_context rsa; mbedtls_entropy_context entropy; mbedtls_ctr_drbg_context ctr_drbg; unsigned char result[1024]; unsigned char buf[512]; const char *pers = "rsa_decrypt"; ((void) argv); memset(result, 0, sizeof( result ) ); mbedtls_ctr_drbg_init( &ctr_drbg ); ret = 1; if( argc != 1 ) { mbedtls_printf( "usage: rsa_decrypt\n" ); #if defined(_WIN32) mbedtls_printf( "\n" ); #endif goto exit; } mbedtls_printf( "\n . Seeding the random number generator..." ); fflush( stdout ); mbedtls_entropy_init( &entropy ); if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy, (const unsigned char *) pers, strlen( pers ) ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret ); goto exit; } mbedtls_printf( "\n . Reading private key from rsa_priv.txt" ); fflush( stdout ); if( ( f = fopen( "rsa_priv.txt", "rb" ) ) == NULL ) { mbedtls_printf( " failed\n ! Could not open rsa_priv.txt\n" \ " ! Please run rsa_genkey first\n\n" ); goto exit; } mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 ); if( ( ret = mbedtls_mpi_read_file( &rsa.N , 16, f ) ) != 0 || ( ret = mbedtls_mpi_read_file( &rsa.E , 16, f ) ) != 0 || ( ret = mbedtls_mpi_read_file( &rsa.D , 16, f ) ) != 0 || ( ret = mbedtls_mpi_read_file( &rsa.P , 16, f ) ) != 0 || ( ret = mbedtls_mpi_read_file( &rsa.Q , 16, f ) ) != 0 || ( ret = mbedtls_mpi_read_file( &rsa.DP, 16, f ) ) != 0 || ( ret = mbedtls_mpi_read_file( &rsa.DQ, 16, f ) ) != 0 || ( ret = mbedtls_mpi_read_file( &rsa.QP, 16, f ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret ); goto exit; } rsa.len = ( mbedtls_mpi_bitlen( &rsa.N ) + 7 ) >> 3; fclose( f ); /* * Extract the RSA encrypted value from the text file */ ret = 1; if( ( f = fopen( "result-enc.txt", "rb" ) ) == NULL ) { mbedtls_printf( "\n ! Could not open %s\n\n", "result-enc.txt" ); goto exit; } i = 0; while( fscanf( f, "%02X", &c ) > 0 && i < (int) sizeof( buf ) ) buf[i++] = (unsigned char) c; fclose( f ); if( i != rsa.len ) { mbedtls_printf( "\n ! Invalid RSA signature format\n\n" ); goto exit; } /* * Decrypt the encrypted RSA data and print the result. */ mbedtls_printf( "\n . Decrypting the encrypted data" ); fflush( stdout ); if( ( ret = mbedtls_rsa_pkcs1_decrypt( &rsa, mbedtls_ctr_drbg_random, &ctr_drbg, MBEDTLS_RSA_PRIVATE, &i, buf, result, 1024 ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_rsa_pkcs1_decrypt returned %d\n\n", ret ); goto exit; } mbedtls_printf( "\n . OK\n\n" ); mbedtls_printf( "The decrypted result is: '%s'\n\n", result ); ret = 0; exit: mbedtls_ctr_drbg_free( &ctr_drbg ); mbedtls_entropy_free( &entropy ); #if defined(_WIN32) mbedtls_printf( " + Press Enter to exit this program.\n" ); fflush( stdout ); getchar(); #endif return( ret ); }