ANDARDS</a></h1>
This function implements X25519, described in RFC 7748.
<h1 class="Sh" title="Sh" id="HISTORY"><a class="selflink" href="#HISTORY">HISTORY</a></h1>
The <b class="Fn" title="Fn">crypto_x25519</b>(), and
  <b class="Fn" title="Fn">crypto_x25519_public_key</b>() functions first
  appeared in Monocypher 0.1.
<h1 class="Sh" title="Sh" id="SECURITY_CONSIDERATIONS"><a class="selflink" href="#SECURITY_CONSIDERATIONS">SECURITY
  CONSIDERATIONS</a></h1>
If either of the long term secret keys leaks, i