ec_sign
ATTRIBUTE_WARN_UNUSED_RET int ec_sign(u8 *sig, u8 siglen, const ec_key_pair *key_pair,
ret = ec_sign(sig, siglen, &key_pair, allocated_buff, (u32)offset, sig_type, hash_type, (const u8*)adata, adata_len);
int (*ec_sign)(int, const unsigned char *, int, unsigned char *,
EC_KEY_METHOD_get_sign(ec_meth, &ec_sign, NULL, NULL);
EC_KEY_METHOD_set_sign(ec_meth, ec_sign, NULL, ecdsa_do_sign);