Siemens SLE4442 chip technology data and theory

One, the main indicators
● 256 bytes of EEPROM organized 
● 32-bit protected memory composition
● 3-byte user password, the password error count: 3 times
● Temperature range: 0 ℃ ~ 70 ℃
● At least 100,000 erase cycles 
● at least 10 years of data retention period 

 Two, a function description
1, write protected areas (first 32 bytes) of each byte can be individually write-protected, write protect the contents can not be changed (ie, curing data).
2, the password check right before all the data can be read, if necessary, can be properly encrypt the data.
3, after checking the password is correct to write or modify.
4, three bytes of user's password, check the correct itself after the change, effective to the card until the next power.
5, the password error counters, the initial value of 3, the password wrong a time check, then cut one, if the counter value is 0, then the card automatically locked, the data is only read out, can no longer change the password can not be checked ; if not zero, there is a password check is correct, restore to the initial value.
6, byte address 21 ~ 26 for the user code, and my company for large customers in this establishing a globally unique code so that users using the uniform distribution (all of the cards can not be modified after leaving the factory).
7, byte address 0 ~ 5,6 ~ 7, before the factory written by the manufacturer, can not be changed.
8, note that the password area in separate sites, not within 0 ~ 256 bytes.
Third, pay attention to matters
1, SLE4442, there are three security mechanisms: user's password, the only code that is written curing. If you do not check the correct password, you can not write data, write data after a write protection (curing) can not be changed. Which is the only code as the system used in IC card identification, can avoid the same type of fake cards into the system.
2, SLE4442 card no password can be read out entire card data, so the design should pay attention to the content encryption, to prevent spoilers identification data format.
3, entire card is not partitioned, the password by checking the correct one will be able to either an address to write or modify data, the design should pay attention to proper curing of data and data content encryption, to prevent damage to data or illegal do not intend to change data.
4, the password check is correct and can be read out. Therefore, the design process must be able to prevent the use of illegal break spoilers run, direct way to read the password to steal passwords. SLE4442 card has now been upgraded to SLE5542 chip card