AT88RF04C-WA1 Atmel, AT88RF04C-WA1 Datasheet - Page 110

• Manufacturer Part Number: AT88RF04C-WA1
• Manufacturer: Atmel

Specifications of AT88RF04C-WA1

• Lead Free Status / RoHS Status: Supplier Unconfirmed

J.6.
J.6.1. Changing Keys
110
Key Sets
CryptoRF has four Key Sets. Each Key Set is associated with four registers in the Configuration Memory. The
Authentication Key is stored in the Secret Seed G
stored in the AAC
response to the Host challenge. The Session Key S
Figure 34.
Figure 34 shows the portion of the Configuration Memory that contains the Key Set registers. The registers shaded in
green can always be read, but cannot be written after personalization. The registers shaded in blue cannot be written
or read after personalization. Note that all of the Security Fuses must be programmed during personalization for the
device secrets to be secure.
Key Set i uses registers AAC
requiring Key Set i for Authentication or Encryption Activation will no longer be accessible.
The Secret Seeds cannot be modified after the Security Fuses are programmed during personalization. The AAC
registers cannot be re-written after the Security Fuses are programmed either. This is true even if the SME option in the
DCR register is enabled.
AT88SC0808/1616/3216/6416CRF, AT88RF04C
$A0
$A8
$50
$58
$60
$68
$70
$78
$80
$88
$90
$98
AAC
AAC
AAC
AAC
Partial Configuration Memory map showing the Key Set Registers.
$0
0
1
2
3
i
register. The Cryptogram C
$1
i
, C
i
, G
$2
i
and S
Session Encryption Key S
Session Encryption Key S
Session Encryption Key S
Session Encryption Key S
i
. If AAC
Secret Seed G
Secret Seed G
Secret Seed G
Secret Seed G
$3
i
register is used during Authentication Activation procedure to store the
Cryptogram C
Cryptogram C
Cryptogram C
Cryptogram C
i
i
register. The Authentication Attempt Counter for Secret Seed G
i
is locked, the Key Set i is permanently disabled and any User Zone
register is used to store the Encryption Activation key.
$4
0
1
2
3
0
1
2
3
0
1
2
3
$5
$6
$7
Cryptography
Secret
5276C–RFID–3/09
i
is