AT88SC0104CA View Datasheet(PDF) - Atmel Corporation
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MFG CO.
'AT88SC0104CA' PDF : 20 Pages View PDF
AT88SC0104CA
12.3.
Password Verification
Passwords may be used to protect READ and/or WRITE access of any user zone. When a valid password is
presented, it is memorized and active until power is turned off, unless a new password is presented or RST becomes
active. There are eight password sets that may be used to protect any user zone. Only one password is active at a
time.
Presenting the correct WRITE password also grants READ access privileges.
12.4.
Authentication Protocol
The access to a user zone may be protected by an authentication protocol. Any one of four keys may be selected to
use with a user zone.
Authentication success is memorized and active as long as the chip is powered, unless a new authentication is
initialized or RST becomes active. If the new authentication request is not validated, the card loses its previous
authentication which must be presented again to gain access. Only the latest request is memorized.
Figure 12. Password and Authentication Operations
Device (Card)
Card Number
AUTHENTICATION
Host (Reader)
COMPUTE Challenge A
VERIFY A
COMPUTE Challenge B
Challenge A
Challenge B
VERIFY RPW
DATA
Checksum (CS)
VERIFY WPW
VERIFY CS
READ ACCESS
WRITE ACCESS
VERIFY B
Read Password (RPW)
VERIFY CS
Write Password (WPW)
DATA
CS
Write DATA
Note:
Authentication and password verification may be attempted at any time and in any order. Exceeding
corresponding authentication or password attempts trial limit renders subsequent authentication or password
verification attempts futile.
13
5200ES–CRYPT–08/09
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