crypto_kem_sntrup761_BYTES
uint8_t kemkey[crypto_kem_sntrup761_BYTES];
if ((r = sshbuf_reserve(buf, crypto_kem_sntrup761_BYTES,
dump_digest("server kem key:", kem_key, crypto_kem_sntrup761_BYTES);
if ((r = sshbuf_reserve(buf, crypto_kem_sntrup761_BYTES,
dump_digest("client kem key:", kem_key, crypto_kem_sntrup761_BYTES);