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Per Westermark
07/13/12 21:36
Read: 632 times
Sweden


 
#187929 - 8-digit code
Responding to: Per Westermark's previous message
Just an addendum - if you have a lock with a 4-digit user-changeable PIN code, then it is also quite normal that there is also a factory-programmed 8-digit code that the user can't change. Each lock with a different 8-digit code, and this code can be used to open the lock even if you have forgotten the 4-digit code.

The user gets a piece of paper specifying the initial 4-digit code (maybe 0000) and that 8-digit code that they should store at a different location as a backup. The factory could potentially keep a list of all serial numbers of produced units, together with the 8-digit master codes - but such a list is hard to make use of: how to verify that it is the legitimate owner of the lock that needs to be told the 8-digit number? And the list is very dangerous to have, in case someone gets access to it.

There should not be any single master PIN that can unlock all locks - such a code is too likely to get out in the wild when someone does something stupid. Like getting their computer pick up a virus.

So your lock that didn't like the removal of the EEPROM probably didn't like that the new EEPROM didn't have an 8-digit backup code and no valid EEPROM checksum/CRC/Adler/...

List of 13 messages in thread
TopicAuthorDate
Password in EEPROM      Arif Deshmukh      07/13/12 17:29      
   Checksum      Per Westermark      07/13/12 21:29      
      8-digit code      Per Westermark      07/13/12 21:36      
         Master Code      Arif Deshmukh      07/13/12 22:35      
            So what does the requirements spec say?      Per Westermark      07/13/12 22:47      
            master codes ....      Erik Malund      07/14/12 01:12      
               This is a low-security lock - or no measly 4-digit PIN      Per Westermark      07/14/12 01:18      
                  language      Erik Malund      07/14/12 08:48      
                     just a thought      Erik Malund      07/14/12 09:09      
                        Never give access when locked      Per Westermark      07/14/12 10:14      
                     PIN + PUK      Per Westermark      07/14/12 10:11      
   The eeprom doesnt hold the password      Jez Smith      07/14/12 19:57      
      High/low security        Per Westermark      07/14/12 23:10      

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