if (key->comment) free(key->comment);
if (key->comment) sfree(key->comment);
void freersakey(struct RSAKey *key) {    if (key->modulus) freebn(key->modulus);    if (key->exponent) freebn(key->exponent);    if (key->private_exponent) freebn(key->private_exponent);    if (key->comment) free(key->comment);}