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gnutls_prf_rfc5705(3) gnutls gnutls_prf_rfc5705(3)


gnutls_prf_rfc5705 - 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);


is a gnutls_session_t type.
length of the label variable.
label used in PRF computation, typically a short string.
length of the extra variable.
optional extra data to seed the PRF with.
size of pre-allocated output buffer to hold the output.
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.




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