ngtcp2_crypto_hkdf_extract
==========================

Synopsis
--------

*#include <ngtcp2/ngtcp2_crypto.h>*

.. function:: int ngtcp2_crypto_hkdf_extract(uint8_t *dest, const ngtcp2_crypto_md *md, const uint8_t *secret, size_t secretlen, const uint8_t *salt, size_t saltlen)

    
    `ngtcp2_crypto_hkdf_extract` performs HKDF extract operation.
    
    The length of output is `ngtcp2_crypto_md_hashlen(md)
    <ngtcp2_crypto_md_hashlen>`.  The output is stored in the buffer
    pointed by *dest*.  The caller is responsible to specify the buffer
    that has enough capacity to store the output.
    
    This function returns 0 if it succeeds, or -1.