10.10.1 Functional

Figure 10-7. Verify Password Command Functional Description

Read password indices: $10 to $17 for passwords 0, 1, 2 and 7.

Write password indices: $00 to $07 for passwords 0, 1, 2 and 7.

Secure code index: $07 (equivalent to Write Password 7).

Four password index bits, "r" and "ppp," indicate the password to compare:

r = 0: Write password
r = 1: Read password
p₂p₁p₀: Password Set Number

Table 10-14. Verify Password Command Structure
Command Structure					Data Sent
CLA	INS : Command	P1	P2	P3	PW1	PW2	PW3
**	$BA	000r 0p₂p₁p₀	**	$30	d₇--- ---d₀	d₁₅--- ---d₈	d₂₃--- ---d₁₆

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 that the command is unauthorized. To prevent replay attacks, the device increments the Associated Attempts Counter before each verification challenge. If the password is correct, the device memorizes this success, clears the attempts counter and returns $90 $00. If the password is incorrect, the device simply returns $69 $00 after incrementing the attempts counter. The Write 7 password is also known as the secure code and must be properly presented before access to the Configuration zone is granted when personalizing the device.