SSL_CTX_SET_DEFAULT_PASSWD_CBOpenSSL_CTX_SET_DEFAULT_PASSWD_CB(3)

NAME    [Toc]    [Back]

       SSL_CTX_set_default_passwd_cb,
       SSL_CTX_set_default_passwd_cb_userdata - set passwd callback
 for encrypted PEM file handling

SYNOPSIS    [Toc]    [Back]

        #include <openssl/ssl.h>

        void     SSL_CTX_set_default_passwd_cb(SSL_CTX      *ctx,
pem_password_cb *cb);
        void SSL_CTX_set_default_passwd_cb_userdata(SSL_CTX *ctx,
void *u);

        int pem_passwd_cb(char *buf, int size, int  rwflag,  void
*userdata);

DESCRIPTION    [Toc]    [Back]

       SSL_CTX_set_default_passwd_cb() sets the default password
       callback called when loading/storing a PEM certificate
       with encryption.

       SSL_CTX_set_default_passwd_cb_userdata() sets a pointer to
       userdata which will be provided to the password callback
       on invocation.

       The pem_passwd_cb(), which must be provided by the application,
 hands back the password to be used during decryption.
 On invocation a pointer to userdata is provided. The
       pem_passwd_cb must write the password into the provided
       buffer buf which is of size size. The actual length of the
       password must be returned to the calling function. rwflag
       indicates whether the callback is used for reading/decryption
 (rwflag=0) or writing/encryption (rwflag=1).

NOTES    [Toc]    [Back]

       When loading or storing private keys, a password might be
       supplied to protect the private key. The way this password
       can be supplied may depend on the application. If only one
       private key is handled, it can be practical to have
       pem_passwd_cb()  handle the password dialog interactively.
       If several keys have to be handled, it can be practical to
       ask for the password once, then keep it in memory and use
       it several times. In the last case, the password could be
       stored into the userdata storage and the pem_passwd_cb()
       only returns the password already stored.

       When asking for the password interactively,
       pem_passwd_cb() can use rwflag to check, whether an item
       shall be encrypted (rwflag=1).  In this case the password
       dialog may ask for the same password twice for comparison
       in order to catch typos, that would make decryption impossible.


       Other items in PEM formatting (certificates) can also be
       encrypted, it is however not usual, as certificate information
 is considered public.
SSL_CTX_SET_DEFAULT_PASSWD_CBOpenSSL_CTX_SET_DEFAULT_PASSWD_CB(3)

RETURN VALUES    [Toc]    [Back]

       SSL_CTX_set_default_passwd_cb() and
       SSL_CTX_set_default_passwd_cb_userdata() do not provide
       diagnostic information.

EXAMPLES    [Toc]    [Back]

       The following example returns the password provided as
       userdata to the calling function. The password is considered
 to be a ' ' terminated string. If the password does
       not fit into the buffer, the password is truncated.

        int pem_passwd_cb(char *buf, int size, int  rwflag,  void
*password)
        {
         strncpy(buf, (char *)(password), size);
         buf[size - 1] = ' ';
         return(strlen(buf));
        }

SEE ALSO    [Toc]    [Back]

       ssl(3), SSL_CTX_use_certificate(3)


OpenBSD 3.6                 2002-05-14                          2