1.cpp

X.509de yingyong 和开发的.具体可以先学习一下.openssl的相关知识

#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <errno.h>
#include <sys/types.h>

#include <winsock2.h>

#include "openssl/rsa.h"
#include "openssl/crypto.h"
#include "openssl/x509.h"
#include "openssl/pem.h"
#include "openssl/ssl.h"
#include "openssl/err.h"
#include "openssl/rand.h"



#define CERTF "client.crt"/*客户端的证书(需经CA签名)*/
#define KEYF "client.key" /*客户端的私钥(建议加密存储)*/
#define CACERT "ca.crt"/*CA 的证书*/
#define PORT  1111/*服务端的端口*/
#define SERVER_ADDR  "192.168.1.103"/*服务段的IP地址*/

#define CHK_NULL(x)  if ((x)==NULL) exit (-1)
#define CHK_ERR(err,s)  if ((err)==-1) { perror(s); exit(-2); }
#define CHK_SSL(err)   if ((err)==-1) { ERR_print_errors_fp(stderr); exit(-3); }

int main ()
{
int err;
int sd;
struct sockaddr_in sa;
SSL_CTX* ctx;
SSL* ssl;
X509*server_cert;
char*str;
char buf [4096];
SSL_METHOD *meth;
int seed_int[100]; /*存放随机序列*/

WSADATA wsaData;

if(WSAStartup(MAKEWORD(2,2),&wsaData) != 0){
printf("WSAStartup()fail:d\n",GetLastError());
return -1;
} 

OpenSSL_add_ssl_algorithms(); /*初始化*/
SSL_load_error_strings(); /*为打印调试信息作准备*/

meth = TLSv1_client_method(); /*采用什么协议(SSLv2/SSLv3/TLSv1)在此指定*/
ctx = SSL_CTX_new (meth); 
CHK_NULL(ctx);

SSL_CTX_set_verify(ctx,SSL_VERIFY_PEER,NULL); /*验证与否*/
SSL_CTX_load_verify_locations(ctx,CACERT,NULL); /*若验证,则放置CA证书*/


if (SSL_CTX_use_certificate_file(ctx, CERTF, SSL_FILETYPE_PEM) <= 0) {
ERR_print_errors_fp(stderr);
exit(-2);
}
if (SSL_CTX_use_PrivateKey_file(ctx, KEYF, SSL_FILETYPE_PEM) <= 0) {
ERR_print_errors_fp(stderr);
exit(-3);
}

if (!SSL_CTX_check_private_key(ctx)) {
printf("Private key does not match the certificate public key\n");
exit(-4);
} 

/*构建随机数生成机制,WIN32平台必需*/
srand( (unsigned)time( NULL ) );
for( int i = 0; i < 100;i )
seed_int[i] = rand();
RAND_seed(seed_int, sizeof(seed_int));

/*以下是正常的TCP socket建立过程 .............................. */
printf("Begin tcp socket...\n");

sd = socket (AF_INET, SOCK_STREAM, 0); CHK_ERR(sd, "socket");

memset (&sa, '\0', sizeof(sa));
sa.sin_family= AF_INET;
sa.sin_addr.s_addr = inet_addr (SERVER_ADDR); /* Server IP */
sa.sin_port= htons (PORT);/* Server Port number */

err = connect(sd, (struct sockaddr*) &sa,
sizeof(sa)); 
CHK_ERR(err, "connect");

/* TCP 链接已建立.开始 SSL 握手过程.......................... */
printf("Begin SSL negotiation \n");

ssl = SSL_new (ctx);
CHK_NULL(ssl);

SSL_set_fd (ssl, sd);
err = SSL_connect (ssl);
CHK_SSL(err);

/*打印所有加密算法的信息(可选)*/
printf ("SSL connection using s\n", SSL_get_cipher (ssl));

/*得到服务端的证书并打印些信息(可选) */
server_cert = SSL_get_peer_certificate (ssl);
CHK_NULL(server_cert);
printf ("Server certificate:\n");

str = X509_NAME_oneline (X509_get_subject_name (server_cert),0,0);
CHK_NULL(str);
printf ("\t subject: s\n", str);
free (str);

str = X509_NAME_oneline (X509_get_issuer_name(server_cert),0,0);
CHK_NULL(str);
printf ("\t issuer: s\n", str);
free (str);

X509_free (server_cert);/*如不再需要,需将证书释放 */

/* 数据交换开始,用SSL_write,SSL_read代替write,read */
printf("Begin SSL data exchange\n");

err = SSL_write (ssl, "Hello World!", strlen("Hello World!")); 
CHK_SSL(err);

err = SSL_read (ssl, buf, sizeof(buf) - 1); 
CHK_SSL(err);

buf[err] = '\0';
printf ("Got d chars:'s'\n", err, buf);
SSL_shutdown (ssl);/* send SSL/TLS close_notify */

/* 收尾工作 */
shutdown (sd,2);
SSL_free (ssl);
SSL_CTX_free (ctx);

return 0;
}