PCF7936AS/3851/C,1-CT NXP Semiconductors, PCF7936AS/3851/C,1-CT Datasheet - Page 20

• Manufacturer Part Number: PCF7936AS/3851/C,1-CT
• Description: pcf7936as series 32-bit 125 khz read / write security...
• Manufacturer: NXP Semiconductors

NXP Semiconductors
Security Transponder (HITAG2)
7.4 Calculation Unit
The PCF7936AS incorporates a Calculation Unit for use
during mutual device authentication, command operation
and EEPROM data exchange, if the device is configured
for Cipher mode. The security algorithm involves a quasi
unique 32 bit Identifier, a 48 bit Secret Key and a 32 bit
Random Number.
The Identifier and the Secret Key are stored in the
Transponder Memory, TM. The Identifier (IDE) is a factory
programmed quasi unique pattern, while the Secret Key is
initialized and subsequently locked by the customer during
device personalization.
2010 May 04
20
Mutual authentication of the Security Transponder in Cipher
mode is triggered by means of the START_AUTH
command, see also section 7.3. As a result, the device
reveals
(basestation) and subsequently the interrogating system
has to send a 32 bit Random Number and a ciphered
Signature to the device. Both are processed by the
Calculation Unit, involving the Secret Key (SK) and
Identifier (IDE), in order to authenticate the interrogating
system. If successful, the device replies with a ciphered
response for validation by the interrogating system.
Details concerning the security algorithm implementation
are specified in a separate Application Note. Please contact
your local NXP representative for more information.
its
Identifier
to
the
Product Specification
interrogating
PCF7936AS
CONFIDENTIAL
system