基於mbedtls-1.3.14庫的rsa公鑰與私鑰生成與加解密，base64編碼與解碼用法介紹
阿新 • • 發佈：2019-10-08
1.1 之前總結了一篇關於AES加密與解密，base64編碼與解碼用法介紹，順便把rsa的用法也總結一下
1.2 用法
#include <stdio.h> #include <stdlib.h> #include <string.h> #include "polarssl/base64.h" #include "polarssl/entropy.h" #include "polarssl/ctr_drbg.h" #include "polarssl/rsa.h" #define DEBUG_INFO(fmt, args...) printf("\033[33m[%s:%s:%d]\033[0m "#fmt"\r\n", __FILE__,__FUNCTION__, __LINE__, ##args) #define KEY_SIZE 1024 #define BUFFER_SIZE 1024 #define EXPONENT 65537 //公鑰 uint8_t rsa_n[BUFFER_SIZE]; uint8_t rsa_e[BUFFER_SIZE]; uint8_t rsa_d[BUFFER_SIZE]; uint8_t rsa_p[BUFFER_SIZE]; uint8_t rsa_q[BUFFER_SIZE]; uint8_t rsa_dp[BUFFER_SIZE]; uint8_t rsa_dq[BUFFER_SIZE]; uint8_t rsa_qp[BUFFER_SIZE]; //公鑰長度 int RSA_N_Len; uint8_t PubKey[1024]; char PubPem[2048]={0}; //讀取rsa key int ReadRsaKey(void) { int ret = 0; rsa_context rsa; FILE *fpriv; RSA_N_Len = 0; memset(rsa_n , 0 ,BUFFER_SIZE); memset(rsa_e , 0 ,BUFFER_SIZE); memset(rsa_d , 0 ,BUFFER_SIZE); memset(rsa_p , 0 ,BUFFER_SIZE); memset(rsa_q , 0 ,BUFFER_SIZE); memset(rsa_dp, 0 ,BUFFER_SIZE); memset(rsa_dq, 0 ,BUFFER_SIZE); memset(rsa_qp, 0 ,BUFFER_SIZE); rsa_init(&rsa, RSA_PKCS_V15, 0); if (( fpriv = fopen("./rsa_key.txt", "rb")) == NULL) { DEBUG_INFO("fopen rsa file failed\n"); ret = -1; goto exit; } if( ( ret = mpi_read_file( &rsa.N , 16, fpriv ) ) != 0 || ( ret = mpi_read_file( &rsa.E , 16, fpriv) ) != 0 || ( ret = mpi_read_file( &rsa.D , 16, fpriv) ) != 0 || ( ret = mpi_read_file( &rsa.P , 16, fpriv ) ) != 0 || ( ret = mpi_read_file( &rsa.Q , 16, fpriv ) ) != 0 || ( ret = mpi_read_file( &rsa.DP, 16, fpriv ) ) != 0 || ( ret = mpi_read_file( &rsa.DQ, 16, fpriv ) ) != 0 || ( ret = mpi_read_file( &rsa.QP, 16, fpriv ) ) != 0 ) { DEBUG_INFO("read rsa file failed\n"); ret = -1; goto exit; } mpi_write_binary(&rsa.N, rsa_n , BUFFER_SIZE); mpi_write_binary(&rsa.E, rsa_e , BUFFER_SIZE); mpi_write_binary(&rsa.D, rsa_d , BUFFER_SIZE); mpi_write_binary(&rsa.P, rsa_p , BUFFER_SIZE); mpi_write_binary(&rsa.Q, rsa_q , BUFFER_SIZE); mpi_write_binary(&rsa.DP, rsa_dp ,BUFFER_SIZE); mpi_write_binary(&rsa.DQ, rsa_dq, BUFFER_SIZE); mpi_write_binary(&rsa.QP, rsa_qp , BUFFER_SIZE); RSA_N_Len = (mpi_msb(&rsa.N)+7) >> 3; memset(PubKey , 0 , BUFFER_SIZE); memcpy(PubKey , &rsa_n[1024-RSA_N_Len] , RSA_N_Len); int n; #if 1 for( n= 1024-RSA_N_Len; n< 1024 ;n++) { printf("%02x" , rsa_n[n]); } printf("\n"); #endif exit: if (fpriv) { fclose(fpriv); } rsa_free(&rsa); return ret; } //生成或者讀取rsa公鑰與私鑰 int CreateRsaKey(void) { int ret = -1; ret = ReadRsaKey(); if (ret == 0) { DEBUG_INFO("ret=%d",ret); return ret; } DEBUG_INFO("ret=%d",ret); RSA_N_Len = 0; memset(rsa_n , 0 ,BUFFER_SIZE); memset(rsa_e , 0 ,BUFFER_SIZE); memset(rsa_d , 0 ,BUFFER_SIZE); memset(rsa_p , 0 ,BUFFER_SIZE); memset(rsa_q , 0 ,BUFFER_SIZE); memset(rsa_dp, 0 ,BUFFER_SIZE); memset(rsa_dq, 0 ,BUFFER_SIZE); memset(rsa_qp, 0 ,BUFFER_SIZE); rsa_context rsa; entropy_context entropy; ctr_drbg_context ctr_drbg; const char *pers = "rsa_genkey"; entropy_init(&entropy); if((ret = ctr_drbg_init( &ctr_drbg, entropy_func, &entropy,(const unsigned char *) pers, strlen( pers))) != 0) { DEBUG_INFO( " failed ! ctr_drbg_init returned %d\n", ret ); goto exit; } DEBUG_INFO( " ok . Generating the RSA key [ %d-bit ]...\n", KEY_SIZE); rsa_init( &rsa, RSA_PKCS_V15, 0 ); if ((ret = rsa_gen_key( &rsa, ctr_drbg_random, &ctr_drbg, KEY_SIZE, EXPONENT)) != 0) { DEBUG_INFO( " failed ! rsa_gen_key returned %d\n\n", ret ); goto exit; } mpi_write_binary(&rsa.N, rsa_n , BUFFER_SIZE); mpi_write_binary(&rsa.E, rsa_e , BUFFER_SIZE); mpi_write_binary(&rsa.D, rsa_d , BUFFER_SIZE); mpi_write_binary(&rsa.P, rsa_p , BUFFER_SIZE); mpi_write_binary(&rsa.Q, rsa_q , BUFFER_SIZE); mpi_write_binary(&rsa.DP, rsa_dp ,BUFFER_SIZE); mpi_write_binary(&rsa.DQ, rsa_dq, BUFFER_SIZE); mpi_write_binary(&rsa.QP, rsa_qp , BUFFER_SIZE); RSA_N_Len = (mpi_msb(&rsa.N)+7) >> 3; memset(PubKey , 0 , BUFFER_SIZE); memcpy(PubKey , &rsa_n[1024-RSA_N_Len] , RSA_N_Len); int n; DEBUG_INFO("rsa.N: "); for( n= 1024-RSA_N_Len; n< 1024 ;n++) { printf("%02x" , rsa_n[n]); } printf("\n"); FILE * fpriv = NULL; if ((fpriv = fopen("./rsa_key.txt", "wb+")) == NULL) { ret = 1; goto exit; } if( ( ret = mpi_write_file( "N = " , &rsa.N , 16, fpriv ) ) != 0 || ( ret = mpi_write_file( "E = " , &rsa.E , 16, fpriv ) ) != 0 || ( ret = mpi_write_file( "D = " , &rsa.D , 16, fpriv ) ) != 0 || ( ret = mpi_write_file( "P = " , &rsa.P , 16, fpriv ) ) != 0 || ( ret = mpi_write_file( "Q = " , &rsa.Q , 16, fpriv ) ) != 0 || ( ret = mpi_write_file( "DP = ", &rsa.DP, 16, fpriv ) ) != 0 || ( ret = mpi_write_file( "DQ = ", &rsa.DQ, 16, fpriv ) ) != 0 || ( ret = mpi_write_file( "QP = ", &rsa.QP, 16, fpriv ) ) != 0 ) { DEBUG_INFO( " failed ! mpi_write_file returned %d\n", ret ); goto exit; } exit: if( fpriv != NULL ) { fclose( fpriv ); } rsa_free( &rsa ); ctr_drbg_free( &ctr_drbg ); entropy_free( &entropy ); return ret; } //rsa 用私鑰解密 int RsaDecrypt(const unsigned char *InBuf , unsigned char* OutBuf) { int ret, c; size_t i; rsa_context rsa; entropy_context entropy; ctr_drbg_context ctr_drbg; const unsigned char *pers = "rsa_decrypt"; ret = 1; entropy_init(&entropy); if(( ret = ctr_drbg_init( &ctr_drbg, entropy_func, &entropy, (const unsigned char *) pers,strlen(pers))) != 0) { DEBUG_INFO( " failed\n ! ctr_drbg_init returned %d\n", ret ); goto exit; } rsa_init(&rsa , RSA_PKCS_V15 , 0); mpi_read_binary(&rsa.N , rsa_n , BUFFER_SIZE); mpi_read_binary(&rsa.E , rsa_e , BUFFER_SIZE); mpi_read_binary(&rsa.D , rsa_d , BUFFER_SIZE); mpi_read_binary(&rsa.P , rsa_p , BUFFER_SIZE); mpi_read_binary(&rsa.Q , rsa_q , BUFFER_SIZE); mpi_read_binary(&rsa.DP , rsa_dp , BUFFER_SIZE); mpi_read_binary(&rsa.DQ , rsa_dq , BUFFER_SIZE); mpi_read_binary(&rsa.QP , rsa_qp , BUFFER_SIZE); rsa.len = (mpi_msb(&rsa.N)+7) >> 3; DEBUG_INFO("rsa.len: %d\n", rsa.len); if( ( ret = rsa_pkcs1_decrypt( &rsa, ctr_drbg_random, &ctr_drbg, RSA_PRIVATE, &i, InBuf, OutBuf, 1024)) != 0 ) { DEBUG_INFO( " failed\n ! rsa_pkcs1_decrypt returned %d\n\n", ret ); goto exit; } DEBUG_INFO( "The RSA decrypted OutBuf is: '%s'\n\n", OutBuf); exit: rsa_free( &rsa ); ctr_drbg_free( &ctr_drbg ); entropy_free( &entropy ); return ret; } //base64解碼，rsa私鑰解密 int Base64DeAndRsa(const unsigned char *Base64, unsigned char *OutBuf) { int ret = -1; size_t num =0; char DataOut2[8000]={0}; base64_decode(NULL , &num , Base64 , strlen(Base64)); ret = base64_decode(DataOut2 , &num , Base64 , strlen(Base64)); if (ret != 0) { DEBUG_INFO("base64 decode failed,ret=%d",ret); return ret; } ret = RsaDecrypt(DataOut2, OutBuf); return ret; } //公鑰轉換pkcs1輸出 void RsaNToPkcs1(char * PemData) { char DataOut[1024]={0}; char PkcsANS[512]={0}; uint8_t Head[]= { 0x30 , 0x81 ,0x9F ,0x30 ,0x0D ,0x06 , 0x09 ,0x2A , 0x86 ,0x48 ,0x86 ,0xF7 ,0x0D ,0x01 ,0x01 ,0x01, 0x05 ,0x00 ,0x03 ,0x81 ,0x8D ,0x00 ,0x30 ,0x81, 0x89 ,0x02 ,0x81 ,0x81, 0x00 }; uint8_t Last[]={0x02 ,0x03 ,0x01, 0x00, 0x01}; memcpy(PkcsANS , Head , sizeof(Head)); memcpy(&PkcsANS[sizeof(Head)], PubKey , RSA_N_Len); memcpy(&PkcsANS[sizeof(Head)+RSA_N_Len] , Last , sizeof(Last)); int size = sizeof(Head) + RSA_N_Len + sizeof(Last); char Base64[1024]={0} ; size_t num = 0; //NULL ,num設為0 ，是為了獲取num base64_encode(NULL , &num, PkcsANS, size); //真正base64編碼 base64_encode(Base64 , &num, PkcsANS, size); int n , i =0 ; for (n = 0 ; n< num ; n++) { if (n!=0 && (n+1)%64 == 0) { DataOut[i] = '\n'; i++; } DataOut[i]= Base64[n]; i++; } sprintf( PemData ,"\n-----BEGIN PUBLIC KEY-----\n%s\n-----END PUBLIC KEY-----\n" , DataOut); DEBUG_INFO("%s" , PemData); } //測試 void TestRsa(void) { CreateRsaKey(); RsaNToPkcs1(PubKey); //採用rsa公鑰加密base64編碼之後的密文，明文是12345678 unsigned char buf[1024] = "qpkO85wYitHwZ/HTm3+DKZmfVm1jZkjwowMIY3rOsXnj6WMSNSKyCRX6aEOUqDHDX7JlqjPctzHYsMBGQyZ5jvKuiLIjIGDQsZtFWg29iXwSz09jhAdixCmiP6JqfMho9zek5FUydqM9tyMQppv8h3ilM8kiFCXRZ2+76PmhSg0="; unsigned char OutBuf[2048] = {0}; //base64解碼，rsa私鑰解密 Base64DeAndRsa(buf,OutBuf); //使用rsa私鑰解密之後 DEBUG_INFO("%s",OutBuf); } int main(void) { TestRsa(); return 0; }
1.3 rsa生成的公鑰，採用pkcs1填充之後，採用網站工具線上加密明文,把加密的密文複製到程式碼中採用私鑰解密
http://tool.chacuo.net/cryptrsapubkey
1.4 解密結果測試，成功解密
