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gnutls_srp_set_server_fake_salt_seed(3)                                 gnutls


NAME

       gnutls_srp_set_server_fake_salt_seed - API function


SYNOPSIS

       #include <gnutls/gnutls.h>

       void
       gnutls_srp_set_server_fake_salt_seed(gnutls_srp_server_credentials_t
       cred, const gnutls_datum_t * seed, unsigned int salt_length);


ARGUMENTS

       gnutls_srp_server_credentials_t cred
                   is a gnutls_srp_server_credentials_t type

       const gnutls_datum_t * seed
                   is the seed data, only needs to be valid until the function
                   returns; size of the seed must be greater than zero

       unsigned int salt_length
                   is the length of the generated fake salts


DESCRIPTION

       This function sets the seed that is used to generate salts for invalid
       (non-existent) usernames.

       In order to prevent attackers from guessing valid usernames, when a
       user does not exist gnutls generates a salt and a verifier and proceeds
       with the protocol as usual.  The authentication will ultimately fail,
       but the client cannot tell whether the username is valid (exists) or
       invalid.

       If an attacker learns the seed, given a salt (which is part of the
       handshake) which was generated when the seed was in use, it can tell
       whether or not the authentication failed because of an unknown
       username.  This seed cannot be used to reveal application data or
       passwords.

        salt_length should represent the salt length your application uses.
       Generating fake salts longer than 20 bytes is not supported.

       By default the seed is a random value, different each time a
       gnutls_srp_server_credentials_t is allocated and fake salts are 16
       bytes long.


SINCE

       3.3.0


REPORTING BUGS

       Report bugs to <bugs@gnutls.org>.
       Home page: https://www.gnutls.org


COPYRIGHT

       Copyright (C) 2001- Free Software Foundation, Inc., and others.
       Copying and distribution of this file, with or without modification,
       are permitted in any medium without royalty provided the copyright
       notice and this notice are preserved.


SEE ALSO

       The full documentation for gnutls is maintained as a Texinfo manual.
       If the /usr/local/share/doc/gnutls/ directory does not contain the HTML
       form visit

       https://www.gnutls.org/manual/

gnutls                               3.7.9
                                       gnutls_srp_set_server_fake_salt_seed(3)

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