-extern rsa_t *rsa_set_hex_public_key(char *n, char *e);
-extern rsa_t *rsa_set_hex_private_key(char *n, char *e, char *d);
-extern rsa_t *rsa_read_pem_public_key(FILE *fp);
-extern rsa_t *rsa_read_pem_private_key(FILE *fp);
+extern rsa_t *rsa_set_hex_public_key(char *n, char *e) __attribute__ ((__malloc__));
+extern rsa_t *rsa_set_hex_private_key(char *n, char *e, char *d) __attribute__ ((__malloc__));
+extern rsa_t *rsa_read_pem_public_key(FILE *fp) __attribute__ ((__malloc__));
+extern rsa_t *rsa_read_pem_private_key(FILE *fp) __attribute__ ((__malloc__));