4442 chip technology information and card parameters

Contactless IC card of a Siemens 4442.
First, key indicators:
● 32-bit protected memory;
● 256 bytes of EEPROM;
● 3-byte user password, the password error count: 3;
● Temperature range: 0 ℃ ~ 70 ℃;
● at least 10 million erase;
● at least 10 years of data retention.
● Operating voltage: 5V.
Second, security features:
1, write-protected area (first 32 bytes) of each byte can be individually write-protected, write protection, the content can not be changed (ie, curing data).
2, the password check right before all the data can be read, if necessary, appropriate encryption of data.
3, after checking the correct password is written or modified.
4, three bytes of the user password, check the correct itself after the change, effective to call up the next card.
5, password error counter, the initial value of 3, check the error code 1, then by 1, if the counter value is 0, then
Card automatically locked, the data just read out, no further changes can not check the password again; if not zero, there is a password check is correct, restore to the initial value.
6-byte address 21 to 26 for the user code, the company can be designed for large users in a globally unique code for this so that users use uniform distribution (all the cards are non factory modification).
7, byte address 0 ~ 5,6 ~ 7, before the factory written by the manufacturer, can not be changed.
Third, pay attention to:
Also addressing the password area, not within 0 to 256 bytes