LinuxGuruz
  • Last 5 Forum Topics
    Replies
    Views
    Last post


The Web Only This Site
  • BOOKMARK

  • ADD TO FAVORITES

  • REFERENCES


  • MARC

    Mailing list ARChives
    - Search by -
     Subjects
     Authors
     Bodies





    FOLDOC

    Computing Dictionary




  • Text Link Ads






  • LINUX man pages
  • Linux Man Page Viewer


    The following form allows you to view linux man pages.

    Command:

    SSL_CTX_set_tmp_rsa_callback

    
           SSL_need_tmp_rsa - handle RSA keys for ephemeral key exchange
    
    
    

    SYNOPSIS

            #include <openssl/ssl.h>
    
            void SSL_CTX_set_tmp_rsa_callback(SSL_CTX *ctx,
                       RSA *(*tmp_rsa_callback)(SSL *ssl, int is_export, int keylength));
            long SSL_CTX_set_tmp_rsa(SSL_CTX *ctx, RSA *rsa);
            long SSL_CTX_need_tmp_rsa(SSL_CTX *ctx);
    
            void SSL_set_tmp_rsa_callback(SSL_CTX *ctx,
                       RSA *(*tmp_rsa_callback)(SSL *ssl, int is_export, int keylength));
            long SSL_set_tmp_rsa(SSL *ssl, RSA *rsa)
            long SSL_need_tmp_rsa(SSL *ssl)
    
            RSA *(*tmp_rsa_callback)(SSL *ssl, int is_export, int keylength);
    
    
    

    DESCRIPTION

           SSL_CTX_set_tmp_rsa_callback() sets the callback function for ctx to be
           used when a temporary/ephemeral RSA key is required to
           tmp_rsa_callback.  The callback is inherited by all SSL objects newly
           created from ctx with <SSL_new(3)|SSL_new(3)>. Already created SSL
           objects are not affected.
    
           SSL_CTX_set_tmp_rsa() sets the temporary/ephemeral RSA key to be used
           to be rsa. The key is inherited by all SSL objects newly created from
           ctx with <SSL_new(3)|SSL_new(3)>. Already created SSL objects are not
           affected.
    
           SSL_CTX_need_tmp_rsa() returns 1, if a temporary/ephemeral RSA key is
           needed for RSA-based strength-limited 'exportable' ciphersuites because
           a RSA key with a keysize larger than 512 bits is installed.
    
           SSL_set_tmp_rsa_callback() sets the callback only for ssl.
    
           SSL_set_tmp_rsa() sets the key only for ssl.
    
           SSL_need_tmp_rsa() returns 1, if a temporary/ephemeral RSA key is
           needed, for RSA-based strength-limited 'exportable' ciphersuites
           because a RSA key with a keysize larger than 512 bits is installed.
    
           These functions apply to SSL/TLS servers only.
    
    
    

    NOTES

           When using a cipher with RSA authentication, an ephemeral RSA key
           exchange can take place. In this case the session data are negotiated
           using the ephemeral/temporary RSA key and the RSA key supplied and
           certified by the certificate chain is only used for signing.
    
           Under previous export restrictions, ciphers with RSA keys shorter (512
           bits) than the usual key length of 1024 bits were created. To use these
           ciphers with RSA keys of usual length, an ephemeral key exchange must
           clients.  It is therefore strongly recommended to not use ephemeral RSA
           key exchange and use EDH (Ephemeral Diffie-Hellman) key exchange
           instead in order to achieve forward secrecy (see
           SSL_CTX_set_tmp_dh_callback(3)).
    
           An application may either directly specify the key or can supply the
           key via a callback function. The callback approach has the advantage,
           that the callback may generate the key only in case it is actually
           needed. As the generation of a RSA key is however costly, it will lead
           to a significant delay in the handshake procedure.  Another advantage
           of the callback function is that it can supply keys of different size
           while the explicit setting of the key is only useful for key size of
           512 bits to satisfy the export restricted ciphers and does give away
           key length if a longer key would be allowed.
    
           The tmp_rsa_callback is called with the keylength needed and the
           is_export information. The is_export flag is set, when the ephemeral
           RSA key exchange is performed with an export cipher.
    
    
    

    EXAMPLES

           Generate temporary RSA keys to prepare ephemeral RSA key exchange. As
           the generation of a RSA key costs a lot of computer time, they saved
           for later reuse. For demonstration purposes, two keys for 512 bits and
           1024 bits respectively are generated.
    
            ...
            /* Set up ephemeral RSA stuff */
            RSA *rsa_512 = NULL;
            RSA *rsa_1024 = NULL;
    
            rsa_512 = RSA_generate_key(512,RSA_F4,NULL,NULL);
            if (rsa_512 == NULL)
                evaluate_error_queue();
    
            rsa_1024 = RSA_generate_key(1024,RSA_F4,NULL,NULL);
            if (rsa_1024 == NULL)
              evaluate_error_queue();
    
            ...
    
            RSA *tmp_rsa_callback(SSL *s, int is_export, int keylength)
            {
               RSA *rsa_tmp=NULL;
    
               switch (keylength) {
               case 512:
                 if (rsa_512)
                   rsa_tmp = rsa_512;
                 else { /* generate on the fly, should not happen in this example */
                   rsa_tmp = RSA_generate_key(keylength,RSA_F4,NULL,NULL);
                   rsa_512 = rsa_tmp; /* Remember for later reuse */
                 }
    
               return(rsa_tmp);
            }
    
    
    

    RETURN VALUES

           SSL_CTX_set_tmp_rsa_callback() and SSL_set_tmp_rsa_callback() do not
           return diagnostic output.
    
           SSL_CTX_set_tmp_rsa() and SSL_set_tmp_rsa() do return 1 on success and
           0 on failure. Check the error queue to find out the reason of failure.
    
           SSL_CTX_need_tmp_rsa() and SSL_need_tmp_rsa() return 1 if a temporary
           RSA key is needed and 0 otherwise.
    
    
    

    SEE ALSO

           ssl(3), SSL_CTX_set_cipher_list(3), SSL_CTX_set_options(3),
           SSL_CTX_set_tmp_dh_callback(3), SSL_new(3), ciphers(1)
    
    
    

    1.0.1e 2016-01-07 SSL_CTX_set_tmp_rsa_callback(3)

    
    
  • MORE RESOURCE


  • Linux

    The Distributions





    Linux

    The Software





    Linux

    The News



  • MARKETING






  • Toll Free

webmaster@linuxguruz.com
Copyright © 1999 - 2016 by LinuxGuruz