at88sc0104c ATMEL Corporation, at88sc0104c Datasheet - Page 17

• Manufacturer Part Number: at88sc0104c
• Description: Cryptomemory Specification For Standard Mode Of Operation
• Manufacturer: ATMEL Corporation

5. Communication Security Modes
5.1
5.1.1
Figure 5-1.
5.1.2
5210A–SMIC–04/07
Security Operations
Password Verification
Mutual Authentication
CryptoMemory Device
Password Verification
Verify Password
Allow Access
Communication between the device and host operates in three basic modes: Standard, Authen-
tication and Encryption Modes. The Standard Mode is the default mode for the device after
power-up. Special procedures exist for enabling Authentication and Encryption Modes but are
beyond the scope of this document. Information pertaining to use of Authentication and Encryp-
tion Modes of CryptoMemory is available from Atmel under Non-Disclosure and/or Limited
Licensing Agreements (NDA and/or LLA).
Table 5-1.
The use of passwords protects read and write accesses to the user zones. Any one of 8 pass-
word sets is available for assignment to any user zone through configuration of access registers.
CryptoMemory provides separate 24-bit passwords for read and write operations. Read pass-
words grant only read accesses to zones under password protection, while write passwords
grant both read and write accesses. Successful presentation of any password renders the verify
password command active until the presentation of another password or device reset. Only one
password may be active at a time. Presenting incorrect passwords decrements the value of the
corresponding password attempts counter (PAC). Decrementing the PAC to $00 permanently
disables the corresponding password and permanently renders the corresponding user zone(s)
under protection inaccessible. Operation in authentication or encryption modes requires encryp-
tion of passwords for all password transactions.
The mutual authentication mode employs cryptographic technology that allows the device to
authenticate the host, and the host to authenticate the device prior to any data communication
between the two. Additional information on using mutual authentication is available from Atmel
under NDA and/or LLA.
Configuration data includes the entire configuration memory except the passwords.
MAC: Message Authentication Code.
Standard/Password
Authentication
Encryption
AT88SC0104/0204/0404/0808/1616/3216/6416/12816/25616C
Mode
Communication Security Modes
Command/Communication
Verify Password
Configuration Data
clear
clear
clear
User Data
encrypted
clear
clear
encrypted if performed
after Mutual Authentication
Send Password
Passwords
encrypted
encrypted
Host Logic
clear
Data Integrity Check
MAC
MAC
n/a
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