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gnutls_prf_rfc5705 - Man Page

API function


#include <gnutls/gnutls.h>

int gnutls_prf_rfc5705(gnutls_session_t session, size_t label_size, const char * label, size_t context_size, const char * context, size_t outsize, char * out);


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.


Exports keying material from TLS/DTLS session to an application, as specified in RFC5705.

In the TLS versions prior to 1.3, it applies the TLS Pseudo-Random-Function (PRF) on the master secret and the provided data, seeded with the client and server random fields.

In TLS 1.3, it applies HKDF on the exporter master secret derived from the master secret.

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.


GNUTLS_E_SUCCESS on success, or an error code.



Reporting Bugs

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

See Also

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



3.8.6 gnutls