OpenSSL实现SSL网络通信-Toy模板网

这篇具有很好参考价值的文章主要介绍了OpenSSL实现SSL网络通信。希望对大家有所帮助。如果存在错误或未考虑完全的地方，请大家不吝赐教，您也可以点击"举报违法"按钮提交疑问。

Certainly! Here are the C language programs for a simple OpenSSL client and server that can establish a secure communication channel between them:
l
inux环境下
OpenSSL Server Program (server.c):

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <openssl/ssl.h>
#include <openssl/err.h>

#define CERT_FILE "server.pem"
#define KEY_FILE "server.key"

void init_openssl() {
    SSL_load_error_strings();
    OpenSSL_add_ssl_algorithms();
}

SSL_CTX* create_context() {
    const SSL_METHOD *method;
    SSL_CTX *ctx;

    method = SSLv23_server_method();
    ctx = SSL_CTX_new(method);
    if (!ctx) {
        perror("Unable to create SSL context");
        ERR_print_errors_fp(stderr);
        exit(EXIT_FAILURE);
    }

    return ctx;
}

void configure_context(SSL_CTX *ctx) {
    SSL_CTX_set_ecdh_auto(ctx, 1);

    if (SSL_CTX_use_certificate_file(ctx, CERT_FILE, SSL_FILETYPE_PEM) <= 0) {
        ERR_print_errors_fp(stderr);
        exit(EXIT_FAILURE);
    }

    if (SSL_CTX_use_PrivateKey_file(ctx, KEY_FILE, SSL_FILETYPE_PEM) <= 0) {
        ERR_print_errors_fp(stderr);
        exit(EXIT_FAILURE);
    }
}

int main() {
    int sockfd, clientfd;
    struct sockaddr_in serv_addr, client_addr;
    socklen_t client_len;
    SSL_CTX *ctx;
    SSL *ssl;

    init_openssl();
    ctx = create_context();

    configure_context(ctx);

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        perror("Unable to create socket");
        exit(EXIT_FAILURE);
    }

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons(8888);

    if (bind(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {
        perror("Unable to bind socket");
        exit(EXIT_FAILURE);
    }

    if (listen(sockfd, 5) < 0) {
        perror("Unable to listen");
        exit(EXIT_FAILURE);
    }

    printf("Server listening on port 8888...\n");

    while (1) {
        client_len = sizeof(client_addr);
        clientfd = accept(sockfd, (struct sockaddr*)&client_addr, &client_len);
        if (clientfd < 0) {
            perror("Unable to accept connection");
            exit(EXIT_FAILURE);
        }

        ssl = SSL_new(ctx);
        SSL_set_fd(ssl, clientfd);

        if (SSL_accept(ssl) <= 0) {
            ERR_print_errors_fp(stderr);
        } else {
            printf("SSL connection established\n");

            char buffer[1024];
            memset(buffer, 0, sizeof(buffer));
            SSL_read(ssl, buffer, sizeof(buffer));
            printf("Received: %s\n", buffer);

            char *response = "Hello from server";
            SSL_write(ssl, response, strlen(response));
            printf("Response sent\n");

            SSL_shutdown(ssl);
            SSL_free(ssl);
        }

        close(clientfd);
    }

    close(sockfd);
    SSL_CTX_free(ctx);
    cleanup_openssl();

    return 0;
}

OpenSSL Client Program (client.c):

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <openssl/ssl.h>
#include <openssl/err.h>

#define SERVER_IP "127.0.0.1"
#define SERVER_PORT 8888

void init_openssl() {
    SSL_load_error_strings();
    OpenSSL_add_ssl_algorithms();
}

SSL_CTX* create_context() {
    const SSL_METHOD *method;
    SSL_CTX *ctx;

    method = SSLv23_client_method();
    ctx = SSL_CTX_new(method);
    if (!ctx) {
        perror("Unable to create SSL context");
        ERR_print_errors_fp(stderr);
        exit(EXIT_FAILURE);
    }

    return ctx;
}

void configure_context(SSL_CTX *ctx) {
    SSL_CTX_set_default_verify_paths(ctx);
}

int main() {
    int sockfd;
    struct sockaddr_in serv_addr;
    SSL_CTX *ctx;
    SSL *ssl;

    init_openssl();
    ctx = create_context();

    configure_context(ctx);

    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        perror("Unable to create socket");
        exit(EXIT_FAILURE);
    }

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERVER_PORTApologies for the abrupt cutoff in the code. Here's the continuation of the OpenSSL client program (client.c):

```c
    if (inet_pton(AF_INET, SERVER_IP, &(serv_addr.sin_addr)) <= 0) {
        perror("Unable to convert server IP address");
        exit(EXIT_FAILURE);
    }

    if (connect(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {
        perror("Unable to connect to server");
        exit(EXIT_FAILURE);
    }

    ssl = SSL_new(ctx);
    SSL_set_fd(ssl, sockfd);

    if (SSL_connect(ssl) <= 0) {
        ERR_print_errors_fp(stderr);
        exit(EXIT_FAILURE);
    }

    printf("SSL connection established\n");

    char *message = "Hello from client";
    SSL_write(ssl, message, strlen(message));
    printf("Message sent\n");

    char buffer[1024];
    memset(buffer, 0, sizeof(buffer));
    SSL_read(ssl, buffer, sizeof(buffer));
    printf("Received: %s\n", buffer);

    SSL_shutdown(ssl);
    SSL_free(ssl);
    close(sockfd);
    SSL_CTX_free(ctx);
    cleanup_openssl();

    return 0;
}

To compile and run the programs, you’ll need to make sure you have the OpenSSL library installed on your system. Use the following command to compile the server and client programs:

gcc -o server server.c -lssl -lcrypto
gcc -o client client.c -lssl -lcrypto

Once compiled, you can run the server and client programs separately in different terminal windows. First, start the server:

./server

Then, in another terminal window, run the client:

./client

You should see the client and server establish an SSL connection and exchange messages securely.

Please let me know if you need any further explanation or examples. If you’re ready, we can proceed to the next section: “SSL Certificates and Keys.”文章来源地址https://www.toymoban.com/news/detail-741487.html

到了这里，关于OpenSSL实现SSL网络通信的文章就介绍完了。如果您还想了解更多内容，请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章，希望大家以后多多支持TOY模板网！