Пример защищённого соединения socket OpenSSL

void InitializeSSL()
{
    SSL_load_error_strings();
    SSL_library_init();
    OpenSSL_add_all_algorithms();
}
 
void DestroySSL()
{
    ERR_free_strings();
    EVP_cleanup();
}
 
void ShutdownSSL(SSL* ssl)
{
    SSL_shutdown(ssl);
    SSL_free(ssl);
}
 
SOCKET socketInit()
{
    SOCKET      s;
    WSADATA     ws;
    sockaddr_in sock_bind;
    WSAStartup(0x0002, &ws);
    s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    ZeroMemory(&sock_bind, sizeof(sock_bind));
    sock_bind.sin_family = PF_INET;
    sock_bind.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    sock_bind.sin_port = htons(1234);
    bind(s, (sockaddr*)&sock_bind, sizeof(sock_bind));
 
    return s;
}
 
SOCKET startListen(SOCKET s)
{
    SOCKET new_conn;
    sockaddr_in new_ca;
    listen(s, MAX_CONN);
    cout << "Wait new connections" << endl;
    ZeroMemory(&new_ca, sizeof(new_ca));
    int size = sizeof(new_ca);
    new_conn = accept(s, (sockaddr*)&new_ca, (int*)&size);
    cout << "Client connected" << endl;
    cout << "Client IP = " << inet_ntoa((in_addr)new_ca.sin_addr) << endl;
    cout << "Client PORT = " << ntohs(new_ca.sin_port) << endl;
 
 
    ////////////////////////
    SSL_CTX *sslctx;
    SSL *cSSL;
 
    InitializeSSL();
    sslctx = SSL_CTX_new(SSLv23_server_method());
    SSL_CTX_set_options(sslctx, SSL_OP_SINGLE_DH_USE);
    int use_cert = SSL_CTX_use_certificate_file(sslctx, "/serverCertificate.pem", SSL_FILETYPE_PEM);
 
    int use_prv = SSL_CTX_use_PrivateKey_file(sslctx, "/serverCertificate.pem", SSL_FILETYPE_PEM);
 
    cSSL = SSL_new(sslctx);
    SSL_set_fd(cSSL, new_conn);
    //Here is the SSL Accept portion.  Now all reads and writes must use SSL
    int ssl_err = SSL_accept(cSSL);
    if (ssl_err <= 0)
    {
        cout << "SSL ERR" << endl;
        ShutdownSSL(cSSL);
    }
    return new_conn;
}

void InitializeSSL()
{
    SSL_load_error_strings();
    SSL_library_init();
    OpenSSL_add_all_algorithms();
}
 
void DestroySSL()
{
    ERR_free_strings();
    EVP_cleanup();
}
 
void ShutdownSSL(SSL* ssl)
{
    SSL_shutdown(ssl);
    SSL_free(ssl);
}
 
SOCKET socketInit()
{
    SOCKET      s;
    WSADATA     ws;
    sockaddr_in sock_bind;
 
    if (FAILED(WSAStartup(0x0002, &ws))) return E_FAIL;
 
    if (INVALID_SOCKET == (s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)))
        ZeroMemory(&sock_bind, sizeof(sock_bind));
 
    sock_bind.sin_family = PF_INET;
    sock_bind.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
    sock_bind.sin_port = htons(1234);
    connect(s, (sockaddr *)&sock_bind, sizeof(sock_bind));
 
 
    SSL_CTX *sslctx;
    SSL *cSSL;
 
    InitializeSSL();
    sslctx = SSL_CTX_new(SSLv23_server_method());
    SSL_CTX_set_options(sslctx, SSL_OP_SINGLE_DH_USE);
    int use_cert = SSL_CTX_use_certificate_file(sslctx, "/serverCertificate.pem", SSL_FILETYPE_PEM);
 
    int use_prv = SSL_CTX_use_PrivateKey_file(sslctx, "/serverCertificate.pem", SSL_FILETYPE_PEM);
 
    cSSL = SSL_new(sslctx);
    SSL_set_fd(cSSL, s);
    //Here is the SSL Accept portion.  Now all reads and writes must use SSL
    int ssl_err = SSL_accept(cSSL);
    if (ssl_err <= 0)
    {
        cout << "SSL ERR" << endl;
        ShutdownSSL(cSSL);
    }
    return s;
}