AT88SC0404C-PI Atmel, AT88SC0404C-PI Datasheet - Page 55

• Manufacturer Part Number: AT88SC0404C-PI
• Manufacturer: Atmel

Specifications of AT88SC0404C-PI

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: PDIP
• Mounting: Through Hole
• Pin Count: 8
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Not Compliant

9.4.9. Verify Password: $BA
54
When the device receives the Verify Crypto command, it computes a challenge based on the received random number,
Q, the internally stored associated Cryptogram, C
also increments the associated attempts counter. It then compares the computed challenge with the challenge sent by
the host. If the challenges match, the device computes and writes a new C
failure information of the authentication process and updates the authentication attempts counter accordingly.
Key index:
Data :
Table 45. Verify Crypto
The device increments the associated attempts counter each time prior to verifying the challenge, to prevent attacks. If
the authentication succeeds, the device memorizes this success, clears the attempts counter and returns $90 $00. If
the authentication fails, the device simply returns $69 $00. If the maximum number of trials has been exceeded, the
device will return $69 $00 instead of the INS code, after receiving the header, to indicate the command is unauthorized.
Functional
Figure 30. Verify Command Functional Description
Read password indices: $10 to $17 for passwords 0 to 7.
Write password indices: $00 to $07 for passwords 0 to 7.
Secure code index: $07 (equivalent to Write 7 Password).
Four password index bits "r" and "ppp" indicate the password to compare:
Atmel AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C
CLA
8-password bytes
**
b0000_00nn : Secret Seed G
b0001_00nn : Session Encryption Key S
Q : Host random number, 8-bytes
CH : Host challenge, 8-bytes
r = 0: Write password
r = 1: Read password
p2p1p0: Password set number
INS : Command
$B8
Verify Crypto
Password Index
Command
0
000e 00nn
Host
PW1
PW2
PW3
-G
3
P1
0
-S
3
i
, and Secret Seed, G
P2
**
Device
$10
P3
d
7
--- ---d
Q1
i
(or Session Encryption Key, S
i
and S
0
d
i
63
. The device utilizes the success or
--- ---d
Q8
Data Sent
56
d
7
--- ---d
CH1
0
5211C–SMIC–01/10
i
). The device
d
63
--- ---d
CH8
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