User's Manual

HF Mifare Easy Module V1.0
ACG Identification Technologies GmbH 53
7.4.3.17 Write master key
This command stores a MIFARE Standard key into the master key memory of the
reader. The reader can store up to 32 keys.
Command
Command Data
'wm' Key number (1 byte) 00h … 1Fh
Key (6 bytes)
Answer
Answer Description
data written key (6 bytes)
'F' Error: Write failure
Example
Command Description
wm00112233445566 Store key 112233445566h in EEPROM (key
number 0).
wm02A0A1A2A3A4A5 Store transport key 1 in EEPROM key 2.
7.4.3.17.1 Writing master keys
Keys are write only. It is not possible to read the keys. Nevertheless the reader
returns correct error messages if the writing process fails.
A verification of the master key can only be done using an appropriate card and a
successful login.
7.4.3.17.2 Using master keys for authentication
Master keys may be used for ISO-14443 A tag authentication. It is possible to use
every stored for key A as well as key B authentication.
Each key is 6 bytes long and stored redundantly for data security.