mbedtls_x25519_calc_secret() function
This function derives and exports the shared secret. This is the last function used by both TLS client and servers.
Arguments
olen
The number of Bytes written.
buf
The destination buffer.
blen
The length of the destination buffer.
Return value
\c 0 on success. An \c MBEDTLS_ERR_ECP_XXX error code on failure.