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Product short data sheet
COMPANY PUBLIC
Rev. 3.1 — 11 December 2014
210331 11 of 21
NXP Semiconductors
HTSICH56; HTSICH48
HITAG S transponder IC
7.5.4 CHALLENGE
By means of the response of the SELECT (UID) command the RWD detects that the
HITAG S Transponder is configured in Authentication Mode (Bit AUT = 1) and starts the
encrypted Challenge sequence.
The Read/Write Device sends a 32 bit Random Number (RND) and a 32 bit secret data
stream to the transponder. In order to perform the secret data stream, a security
co-processor is required on the read/write Device.
If the received secret data stream corresponds with the secret data stream calculated by
the HITAG S Transponder, a 32 bit Secret Response (secret data stream encrypting the
configuration byte CON 2, password high byte PWDH 0 and password low Bytes PWDL 0
and PWDL 1) is transmitted after the SOF.
The response of the HITAG S Transponder is transmitted in Manchester Coding (MC).
Table 8. Challenge
MSB LSB MSB LSB
RWD: 32 Bit RND 32 Bit Secret Data EOF
MSB LSB MSB LSB MSB LSB MSB LSB MSB LSB
Transponder: t
wresp
SOF CON 2 PWDH 0 PWDL 0 PWDL 1 CRC 8
32 Bit secret response
