mix_dh
if (!mix_dh(handshake->chaining_key, key, handshake->ephemeral_private,
if (!mix_dh(chaining_key, key, wg->static_identity.static_private, e))
if (!mix_dh(handshake->chaining_key, NULL, handshake->ephemeral_private,
if (!mix_dh(handshake->chaining_key, NULL, handshake->ephemeral_private,
if (!mix_dh(chaining_key, NULL, ephemeral_private, e))
if (!mix_dh(chaining_key, NULL, wg->static_identity.static_private, e))