advantages of using auto-update:
- it automatically updates when keys change! By contrast, with fixed-key cards some kind of manual intervention is required to update keys periodically (eg re-programming the card, or entering new keys via the remote-control unit).
disadvantgages of auto-update:
- tends to be more complex code so can leave less room for actual keys in the eeprom/pic
- vulnerable to false-key updates by providers
- requires master/management/op-keys of some description to be known and they are much more difficult to come by (and more dangerous to publish) than the fixed keys.
2old