ECDH_size
int ECDH_size(const EC_KEY *ecdh);
if ((buf_len = ECDH_size(ecdh)) < BN_num_bytes(x)) {
LCRYPTO_ALIAS(ECDH_size);
LCRYPTO_USED(ECDH_size);
if ((key_len = ECDH_size(ecdh)) <= 0)
out_len = ECDH_size(key);
if ((len = ECDH_size(keya)) != ECDH_size(keyb))