AT88SC25616C-DK Atmel, AT88SC25616C-DK Datasheet - Page 17

• Manufacturer Part Number: AT88SC25616C-DK
• Description: KIT DEV CRYPTOMEMORY SMARTCARD
• Manufacturer: Atmel
• Series: CryptoMemory®r
• Type: Crypto and Secure Memoryr

Specifications of AT88SC25616C-DK

• Contents: PC/SC Card Reader, Sample Cards, API, Documentation and Tutorial
• For Use With/related Products: AT88SC Family
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: AT88SC25616CDK; AT88SC25616CDK

5.1.3
5.1.4
5.2
5.2.1
5.2.2
5.2.3
Figure 5-2.
14
Address
$080
Data Protection Features
AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C
Data Encryption
Encrypted Checksum
Modify Forbidden
Program Only
Write Lock
Write Lock example
110110011
$0
The encryption mode builds upon the mutual authentication mode such that the host and device
first authenticate each other and go further to encrypt all data communications between them.
Additional information on using the encryption mode is available from Atmel under NDA and/or
LLA.
The encrypted checksums allows for bidirectional data validity and integrity check between the
host and device. Additional information on using encrypted checksums is available from Atmel
under NDA and LLA.
Security operations control access to data stored in CryptoMemory. After gaining access, addi-
tional options exist to protect data in the user memory.
The Modify Forbidden option renders the user zone read-only by restricting all write operations
to it. It is recommended to program all required data in the user zone prior to enabling this
option. Modify Forbidden is available for any user zone and is selectable by configuring appro-
priate Access Registers.
The Program Only option constrains data bit modification to programming from logic “1” to logic
“0” only. Data bits may never change from logic “0” to logic “1”. Program Only is available for
any user zone and is selectable by configuring appropriate Access Registers.
The Write Lock option provides ability to render individual bytes within a user zone read-only by
restricting all write operations to it. It operates on 8-byte page level whereby the lowest
addressed byte of the page serves as the write access control byte for that page. Figure 5-2
shows the use of write lock for data at addresses $080 - $087. The byte at $080 controls write-
access to bytes from $080 to $087.
The Write Lock option also applies to the access control byte for each page by writing its least
significant (rightmost) bit to logic “0”. Moreover, only logic modifications from logic “1” to logic “0”
of the access control byte are permissible.
xxxx xxxx
locked
$1
xxxx xxxx
locked
$2
xxxx xxxx
$3
xxxx xxxx
$4
xxxx xxxx
locked
$5
xxxx xxxx
$6
5210B–SMIC–11/08
xxxx xxxx
$7