PCF7936AS/3851/C,1-CT NXP Semiconductors, PCF7936AS/3851/C,1-CT Datasheet - Page 9

• 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)
7.1.3 Secret Key, SK
The Secret Key, SK is applicable in Cipher mode only
(ENC = 1). The Secret Key is a 48 bit pattern, which
typically is initialized and subsequently locked by the
customer during device personalization. The Secret Key is
located in page 1 and 2, see Figure 4.
The 32 least significant bits of SK (bit 31 to bit 0) are
located in page 1 while the 16 most significant bits (bit 47 to
bit 32) are located in page 2 at bit address 0 to 15.
The Immobilizer Secret Key is incorporated in the process
of device authentication and used by the on-chip
calculation unit as well as by the interrogating system.
However the Immobilizer Secret Key is never transmitted
during the process of device authentication. For details
refer to section 7.3.1, START_AUTH command.
The Secret Key may be assigned any value that is
considered useful by the application. The SK can be
protected against reading and writing by setting the lock bit
SKL, see section 7.1.4
7.1.4 Transponder and Memory Configuration, TMCF
Access to the Transponder Memory, TM, and device
configuration is controlled by a set of configuration bits,
TMCF, located in page 3, see Figure 6.
The memory access rights applied by TMCF affect the
behavior of READ_PAGE and WRITE_PAGE commands
only.
authentication process, is not affected at all.
Secret Key Lock, SKL
If set, the Password Basestation, PSW B, (Password
mode) or the Secret Key, SK, (Cipher mode) is irreversible
locked against reading and writing (OTP like). If set once,
its value can no longer be read or altered.
2010 May 04
Figure 6. Transponder Memory Configuration, TMCF
Device
bit 31
MSB
30 29 28 27 26 25
operation,
e.g.
with
LSB
24
respect
TMCF
to
the
9
Page 3 Lock, PG3L
If set, page 3 is irreversible locked against writing (OTP
like). Thus if set once, the Transponder and Memory
Configuration
Transponder (PSW
reading is supported in any case.
Protect Write User Page 4 and 5, PWP1
If set, a write protection is assigned for the user pages
page 4 and 5 (USER0 and USER1). As a result its content
cannot be altered, however, reading is supported in any
case.
If cleared, page 4 and page 5 support reading and writing.
The content and organization of the user pages is fully
determined by the application.
Protect Write User Page 6 and 7, PWP0
If set, a write protection is assigned for the user pages
page 6 and 7 (USER2 and USER3). As a result its content
cannot be altered, however, reading is supported in any
case.
If cleared, page 6 and page 7 support reading and writing.
The content and organization of the user pages is fully
determined by the application.
Enable Cipher Mode, ENC
The device may be configured for to perform authentication
in either Password mode or Cipher mode.
If ENC is set, Cipher mode is selected, otherwise Password
mode.
Thus, ENC affects operation of the START_AUTH
command and whether plain or ciphered transmission of
data and commands is supported, for details refer to
section 7.3.1.
(TMCF)
T
) can no longer be altered. However,
as
well
Product Specification
as
PCF7936AS
CONFIDENTIAL
the
Password