Freertos RSA公钥解密

1. RSA算法所需要最小内存

   2K ram + 12K rom

2. Aes加密算法所需要最小内存

   10Kram + 13K rom

3. Rsa公约提取模和指数

   链接：http://tool.chacuo.net/cryptrsakeyparse

4. Hex to Base64转换链接

   
   

5. AES公钥解密算法， 随机数使用自己实现函数

如果随机数生成使用mbedtls_ctr_drbg_random，需要依赖aes模块

代码块

#include "mbedtls/config.h"

#include "mbedtls/platform.h"

#include "mbedtls/rsa.h"

#include "mbedtls/entropy.h"

#include "mbedtls/ctr_drbg.h"

#include 

unsigned char g_szModulus[] = "C38E2CD8DB8CC677BDDDB150AB34F48E4C0EDCF82E820BCF6D8F49CB"

 "7252C1B803414144485B2E7B44DF6D7B27225FE521A9EFB391AA9C57"

 "C58659657139858C34A40DCAE7002D5201B79732D5F0E0B1947E98C2"

 "C16EC39EE159E577191F87D8C405515A94E7843A7F3E744576C80F68"

 "3B8A10D0DDE0BE1EBC793A46D870CA21";

unsigned char g_szIndex[] = "10001";

static int g_iIndex = 12;

int random( void *p_rng, unsigned char *output, size_t output_len)

{

 g_iIndex++;

 *output = g_iIndex % gettime();

 if (*output == 00) {

 *output = 48;

 }

 printf("random %d  %02x\n", output_len, *output);

 return 0;

}

int MT_rsa_Test()

{

 int ret = 1;

 int exit_code = MBEDTLS_EXIT_FAILURE;

 size_t i;

 mbedtls_rsa_context rsa;

 //mbedtls_entropy_context entropy;

 mbedtls_ctr_drbg_context ctr_drbg;

 unsigned char input[1024];

 unsigned char buf[512];

 const char *pers = "rsa_encrypt";

 mbedtls_mpi N, E;

 printf( "MT_rsa_Test 1\n");

 mbedtls_mpi_init( &N ); mbedtls_mpi_init( &E );

 mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );

 //mbedtls_ctr_drbg_init( &ctr_drbg );

 //mbedtls_entropy_init( &entropy );

#if 1

 //ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func,

 //                             &entropy, (const unsigned char *) pers,

 //                             strlen( pers ) );

 ret = 0;

 if( ret != 0 )

 {

 printf( " failed\n  ! mbedtls_ctr_drbg_seed returned %d\n", ret );

 goto exit;

 }

 if( ( ret = mbedtls_mpi_read_string( &N, 16, g_szModulus) ) != 0 ||

 ( ret = mbedtls_mpi_read_string( &E, 16, g_szIndex) ) != 0 )

 {

 printf( " failed\n  ! mbedtls_mpi_read_string returned %d\n\n",

 ret );

 goto exit;

 }

 if((ret = mbedtls_rsa_import( &rsa, &N, NULL, NULL, NULL, &E)) != 0)

 {

 printf( " failed\n  ! mbedtls_rsa_import returned %d\n\n", ret);

 goto exit;

 }

 sprintf(input, "1234567890");

 /*

 * Calculate the RSA encryption of the hash.

 */

 printf( "\n  . Generating the RSA encrypted value\n");

 /*mbedtls_ctr_drbg_random*/

 ret = mbedtls_rsa_pkcs1_encrypt( &rsa, random,

 &ctr_drbg, MBEDTLS_RSA_PUBLIC,

 strlen(input), input, buf );

 if( ret != 0 )

 {

 printf(" failed\n  ! mbedtls_rsa_pkcs1_encrypt returned %d\n\n", ret);

 goto exit;

 }

 for( i = 0; i < rsa.len; i++ )

 printf("%02X%s", buf[i],

 ( i + 1 ) % 16 == 0 ? "\r\n" : " " );

 printf( "\n  . Done\n\n");

 exit_code = MBEDTLS_EXIT_SUCCESS;

exit:

 mbedtls_mpi_free( &N );

 mbedtls_mpi_free( &E );

 // mbedtls_ctr_drbg_free( &ctr_drbg );

 //mbedtls_entropy_free( &entropy );

 mbedtls_rsa_free( &rsa );

#endif 

 return( exit_code );

}