| ??? 07/14/12 04:47 Read: times |
#187931 - So what does the requirements spec say? Responding to: ???'s previous message |
Arif Deshmukh said:
Sine I am designing around PIC which has a built in EEPROM, so it also required to store a checksum/CRC byte to internal EEPROM or only four digit code sufficient? Well - the difference between you and me is that it is you who are designing. So it must obviously be you who make the decisions what is sufficient or not. Unless you have a written requirements specification to fulfill. In this system there will be two code, one is user code and second is master code. Both the codes are of four digits. If user code is forgotten then by master code person can open a safe. It is really not smart to have a 4-digit master code. 4 digits represents a very small numeric range. And another thing is that having the master code 4 digits too means that a user who enters the 4 digit normal code and types wrong and opens the lock will have learned the master code. So an employee can, by accident, learn the master code. Which means that when the normal code is later changed, that user can still open the lock with the learned master code. I want to know since PIC has a inbuilt EEPROM so still in this case checksum/CRC is necessary or without it. Why do you think it is relevant if the EEPROM is internal or external? |
| Topic | Author | Date |
| Password in EEPROM | 01/01/70 00:00 | |
| Checksum | 01/01/70 00:00 | |
| 8-digit code | 01/01/70 00:00 | |
| Master Code | 01/01/70 00:00 | |
| So what does the requirements spec say? | 01/01/70 00:00 | |
| master codes .... | 01/01/70 00:00 | |
| This is a low-security lock - or no measly 4-digit PIN | 01/01/70 00:00 | |
| language | 01/01/70 00:00 | |
| just a thought | 01/01/70 00:00 | |
| Never give access when locked | 01/01/70 00:00 | |
| PIN + PUK | 01/01/70 00:00 | |
| The eeprom doesnt hold the password | 01/01/70 00:00 | |
High/low security | 01/01/70 00:00 |