label used in PRF computation, typically a short string.
non-0 if server random field should be first in seed
length of the extra variable.
const char * extra
optional extra data to seed the PRF with.
size of pre-allocated output buffer to hold the output.
char * out
pre-allocate buffer to hold the generated data.
Apply the TLS Pseudo-Random-Function (PRF) using the master secret
on some data, seeded with the client and server random fields.
The label variable usually contain a string denoting the purpose
for the generated data. The server_random_first indicate whether
the client random field or the server random field should be first
in the seed. Non-0 indicate that the server random field is first,
0 that the client random field is first.
The extra variable can be used to add more data to the seed, after
the random variables. It can be used to tie 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.