Forum › MIFARE SDK › Change Key › Reply To: Change Key
Hi Fiore,
First of all, the term “session key” has a different meaning for me. A session key is negotiated between the reader and the card after a successful authenticate. This key is temporary and becomes invalid after the session terminates (the card is removed or a new authenticate takes place).
I do not understand what you means with “Authentication App MasterKey to generate the sessionKey_1”. How do you “generate” keys?
If you provide different keys for the access permissions of your files, then this are “application keys” for me and this keys never have a temporary character. Okay, you should follow the rule: if you change application keys, you must have selected always the application before. Before you can change for instance key #2, you have to authenticate with old key #2 to prove you are allowed to change the key (this prevents the unauthorized write-over of keys). Then you can change the key #2 with the new value. If you want to change the master key, you have to select AID = 0 before, authenticate with the old key and change the key.
The MIFARE Team
First of all, the term “session key” has a different meaning for me. A session key is negotiated between the reader and the card after a successful authenticate. This key is temporary and becomes invalid after the session terminates (the card is removed or a new authenticate takes place).
I do not understand what you means with “Authentication App MasterKey to generate the sessionKey_1”. How do you “generate” keys?
If you provide different keys for the access permissions of your files, then this are “application keys” for me and this keys never have a temporary character. Okay, you should follow the rule: if you change application keys, you must have selected always the application before. Before you can change for instance key #2, you have to authenticate with old key #2 to prove you are allowed to change the key (this prevents the unauthorized write-over of keys). Then you can change the key #2 with the new value. If you want to change the master key, you have to select AID = 0 before, authenticate with the old key and change the key.
The MIFARE Team
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