Reference Manual


Desfire.ChangeKey

Modifies a DESFire card key defined in the SAM or crypto memory.

Properties

Parameters (request frame)

Name Type/Size Description
- Bit mask (8 bits) -
RFU Integer (bit mask area 0xF8) Zero padding
IsKeySet Boolean (bit 0x04) Only needed for Desfire EV2 with multiple Keysets. If true,the reader executes the Desfire "ChangeKeyEV2" command instead of the Desfire "ChangeKey" command.
IsMasterKey Boolean (bit 0x02) Has to be set if the key to change is the PICC Master Key.
IsChangeKey Boolean (bit 0x01)

Has to be set if the key used to authenticate the card is the key that needs to be changed (as specified in KeyNo ).

In this case, the parameter CurKeyIdx has to be omitted.

KeyNr Integer (8 bits) Number of card key (0-13) to change.
- Bit mask (8 bits) -
RFU Integer (bit mask area 0xE0) Zero padding
NewKeyDivMode Enumeration (bit mask area 0x18) Specifies diversification algorithm.
Values:
  • SamAv1OneRound (0)
    SAM AV1 mode for all key types / one encryption round for DES keys.
  • SamAv1TwoRounds (1)
    SAM AV1 mode only for DES keys - two encryption rounds.
  • SamAv2 (2)
    SAM AV2 mode.
RFU Integer (bit 0x04) Zero padding
NewKeyHasDivData Boolean (bit 0x02) Activates key diversification according to NXP AN10922.
NewKeyHasExtIdx Boolean (bit 0x01) Activates key memory expansion.
NewKeyIdx Integer (8 bits) Index of key in the reader's SAM or crypto memory (configuration range 0x00-0xBF).
- Bit mask (8 bits) -
RFU Integer (bit mask area 0xE0) Zero padding
CurKeyDivMode Enumeration (bit mask area 0x18) Specifies diversification algorithm.
Values:
  • SamAv1OneRound (0)
    SAM AV1 mode for all key types / one encryption round for DES keys.
  • SamAv1TwoRounds (1)
    SAM AV1 mode only for DES keys - two encryption rounds).
  • SamAv2 (2)
    SAM AV2 mode.
RFU Integer (bit 0x04) Zero padding
CurKeyHasDivData Boolean (bit 0x02) Activates key diversification according to NXP AN10922.
CurKeyHasExtIdx Boolean (bit 0x01) Activates key memory expansion.
CurKeyIdx Integer (8 bits) Index of key in the reader's SAM or crypto memory (configuration range 0x00-0xBF).
Optional field, condition: NewKeyHasDivData
Length of NewKeyDivData Integer (8 bits) Length of NewKeyDivData in bytes
NewKeyDivData Raw data Diversification data of the new key.
Optional field, condition: CurKeyHasDivData
Length of CurKeyDivData Integer (8 bits) Length of CurKeyDivData in bytes
CurKeyDivData Raw data Diversification data of the current key.
Optional field, condition: NewKeyHasExtIdx
NewKeyExtIdx Integer (8 bits)

Crypto Memory Index (SAM or CryptoMemory) of new key

  • SAM: Key version (0..0xFF)
  • Crypto Memory: Page (0..15)
Optional field, condition: CurKeyHasExtIdx
CurKeyExtIdx Integer (8 bits)

Crypto Memory Index (SAM or CryptoMemory) of current key

  • SAM: Key version (0..0xFF)
  • Crypto Memory: Page (0..15)
Optional field, condition: IsKeySet
KeySet Integer (8 bits) specifies a KeySet (needed for multiple keysets - EV2 extension).

Returned values (response frame)

None