extern bool ecdsa_write_pem_public_key(ecdsa_t *ecdsa, FILE *fp);
extern bool ecdsa_write_pem_private_key(ecdsa_t *ecdsa, FILE *fp);
extern bool ecdsa_write_pem_public_key(ecdsa_t *ecdsa, FILE *fp);
extern bool ecdsa_write_pem_private_key(ecdsa_t *ecdsa, FILE *fp);