gnutls_prf_early(3) — Linux manual page

NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | RETURNS | SINCE | REPORTING BUGS | COPYRIGHT | SEE ALSO | COLOPHON

gnutls_prf_early(3)                gnutls                gnutls_prf_early(3)

NAME top

       gnutls_prf_early - API function

SYNOPSIS top

       #include <gnutls/gnutls.h>

       int gnutls_prf_early(gnutls_session_t session, size_t label_size,
       const char * label, size_t context_size, const char * context, size_t
       outsize, char * out);

ARGUMENTS top

       gnutls_session_t session
                   is a gnutls_session_t type.

       size_t label_size
                   length of the  label variable.

       const char * label
                   label used in PRF computation, typically a short string.

       size_t context_size
                   length of the  extra variable.

       const char * context
                   optional extra data to seed the PRF with.

       size_t outsize
                   size of pre-allocated output buffer to hold the output.

       char * out  pre-allocated buffer to hold the generated data.

DESCRIPTION top

       This function is similar to gnutls_prf_rfc5705(), but only works in
       TLS 1.3 or later to export early keying material.

       Note that the keying material is only available after the ClientHello
       message is processed and before the application traffic keys are
       established.  Therefore this function shall be called in a handshake
       hook function for GNUTLS_HANDSHAKE_CLIENT_HELLO.

       The  label variable usually contains a string denoting the purpose
       for the generated data.

       The  context variable can be used to add more data to the seed, after
       the random variables.  It can be used to make sure the generated
       output is strongly connected to some additional data (e.g., a string
       used in user authentication).

       The output is placed in  out , which must be pre-allocated.

       Note that, to provide the RFC5705 context, the  context variable must
       be non-null.

RETURNS top

       GNUTLS_E_SUCCESS on success, or an error code.

SINCE top

       3.6.8

REPORTING BUGS top

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

COPYRIGHT top

       Copyright © 2001-2019 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 top

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

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

COLOPHON top

       This page is part of the GnuTLS (GnuTLS Transport Layer Security
       Library) project.  Information about the project can be found at 
       ⟨http://www.gnutls.org/⟩.  If you have a bug report for this manual
       page, send it to bugs@gnutls.org.  This page was obtained from the
       tarball gnutls-3.6.9.tar.xz fetched from
       ⟨http://www.gnutls.org/download.html⟩ on 2020-08-13.  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

gnutls                              3.6.9                gnutls_prf_early(3)