Starting to use OpenSSL

Question

I want to use SSL in my cross-platform program. I decided to use OpenSSL.

I have OpenSSL installed, and at this point I look through the code and documentation, trying to figure out how to use the library.

Do you have any resources or simple programs or tutorials that will help me integrate OpenSSL with my program?

Answer 1

Very rude guide:

• Create a new SSL_CTX with SSL_CTX_new() ;
• (server only) Download the SSL_CTX_use_certificate_file() certificate;
• (server only) Download the private key SSL_CTX_use_PrivateKey_file() ;
• Establish a network connection;
• Create a new SSL with SSL_new() ;
• Set the file descriptor of the SSL file to your network connection file using SSL_set_fd() ;
• (client only) Call SSL_connect() ;
• (server only) Call SSL_accept() .

Then use SSL_read() and SSL_write() to read and write from the connection and end with SSL_shutdown() . SSL_CTX can be reused to create SSL objects for many concurrent sessions.

Answer 2

On this page you can find useful OpenSSL commands:

http://www.networking4all.com/en/support/ssl+certificates/manuals/openssl/openssl+commands/

Answer 3

from the “very rude manual” that you mentioned, I managed to achieve, before successful SSL confirmation, between the Mozilla web browser and my server (encoded in c). But after SSL_accept, when I try to use SSL_read to get the browser header of the part, I get unnecessary values ​​and bytes read are zero. below code, calling SSL_accept is successful, but SSL_read is not ..

  if(SSL_set_fd(ssl, client_s)<0) printf("\n error in assigning socket to SSL:"); else printf("\n The socket has been assigned to SSL Structure"); /* Perform SSL Handshake on the SSL server */ err = SSL_accept(ssl); printf("\n Value of err is %d",err); RETURN_ERR(err,"SSL_accept"); if(err==1) printf("\n The ssl connection/Handshake has been successful"); else printf("\n The ssl connection was not successful"); /* Informational output (optional) */ printf("\n SSL connection using %s\n", SSL_get_cipher (ssl)); /*receive the data from the client*/ //err = SSL_accept(ssl); while(i<5) { err = SSL_read(ssl, in_buf, strlen(in_buf)); printf("\n value of err is %d",err); RETURN_ERR(err,"SSL_read"); printf("\n The details from the server is\n: %s,\n Bytes Read : %d",in_buf,err); if(err<0) printf("\n Not Successfully received clients information"); i++; } err = SSL_shutdown(ssl); /* Terminate communication on a socket */ err = close(server_s); /* Free the SSL structure */ SSL_free(ssl); /* Free the SSL_CTX structure */ SSL_CTX_free(ctx); return(0); }