AT88RF04C-MY1G View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT88RF04C-MY1G

CryptoRF® Specification

Atmel Corporation 

Table 90. Authentication Attempt Counter Coding for 88RF PICCs.

AAC Register

Description

$55

No Failed Attempts

$56

1 Failed Attempt

$59

2 Failed Attempts

$5A

3 Failed Attempts

$65

4 Failed Attempts

$66

5 Failed Attempts

$69

6 Failed Attempts

$6A

7 Failed Attempts

$95

8 Failed Attempts

$96

9 Failed Attempts

$99

10 Failed Attempts

$9A

11 Failed Attempts

$A5

12 Failed Attempts

$A6

13 Failed Attempts

$A9

14 Failed Attempts

$AA

15 Failed Attempts (LOCK)

All Other Values Are Not Supported

J.8.

Authentication Activation

Authentication Communication Security is activated using the following Mutual Authentication procedure.

1. The Host reads the PICC ID from Nc (or another equivalent memory location) and calculates the diversified key

matching the PICC Secret Seed G. G = F1(K, ID, x, y, z)

2. The Host reads AACi and Ci from card.

3. The Host generates a Random Number QA and calculates challenge CHA and other parameters with the

cryptographic engine: [CHA, CA, SA] = F2(G, C, QA)

4. The Host Sends Verify Crypto Command with Key Index $0i: Verify Crypto ($0i, QA, CHA)

5. The PICC calculates challenge CH and other parameters using QA from the host with the cryptographic engine:

[CH, CiA, SiA] = F2(Gi, Ci, QA)

6. The PICC compares the internally calculated challenge CH to the value received from the host. If CH = CHA then

the host is authenticated and the card writes the calculated values of CiA to the Ci register and SiA to the Si register.

The AACi is cleared, Authentication Communication Security mode is activated, and an ACK response is returned

to the host.

7. The Host reads the new AACi and CiA from Ci register of the PICC and compares it to the calculated CA from step

3. If CA = CiA then the card is authenticated. The Mutual Authentication procedure is complete.

The Secret Seed Gi value in the PICC never changes after it is locked at personalization. The AACi, and Ci registers

are written (by the PICC) each time a Verify Crypto command is received by the PICC. The Si register is written (by the

PICC) each time the Mutual Authentication procedure succeeds.

If the Host receives a NACK response from the PICC, then the Mutual Authentication procedure can be retried starting

with step 2.

Figure 35 shows the Mutual Authentication procedure as a flowchart.

112 AT88SC0808/1616/3216/6416CRF, AT88RF04C

5276C–RFID–3/09

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