int ecp_util_key_save(ECPContext *ctx, ECPDHKey *key, char *filename);
int ecp_util_key_load(ECPContext *ctx, ECPDHKey *key, char *filename);

int ecp_util_node_save(ECPContext *ctx, ECPNode *node, char *filename);
int ecp_util_node_load(ECPContext *ctx, ECPNode *node, char *filename);