
Specifications of the HT2 MOA3 S20
Rev. 1.1
1997-08-19
Ht2moa3.doc/HS
Page 17 of 22
5.4 Definition of Passwords and Keys
Keys are cryptographic codes, which determine data encryption during data transfer between
read/write device and transponder. They are used to select a HITAG 2 transponder in Crypto
Mode. The 16 bit KEY HIGH and 32 bit KEY LOW form one 48 bit key which has to be
identical on both the transponder and the read/write device.
Passwords are needed to select a HITAG 2 transponder in Password Mode. There is one pair of
passwords (Password TAG, Password RWD) which has to be identical both on the transponder
and the read/write device.
Password TAG:
Password that the transponder sends to the read/write device and which
may be verified by the latter (depending on the configuration of the
read/write device).
Password RWD:
Password that the read/write device sends to the transponder and which is
checked for identity by the latter.
It is important that the following values are in accordance with each other, i.e. the respective data
on the read/write device and on the transponder have to be identical pairs.
HITAG 2 in Password mode:
on the
read/write
device
on the
transponder
Password RWD
Password RWD
as an option (depending on the configuration of the read/write device):
Password TAG
Password TAG
HITAG 2 in Crypto mode:
on the
read/write
device
on the
transponder
KEY LOW
KEY LOW
KEY HIGH
KEY HIGH
as an option (depending on the configuration of the read/write device):
Password TAG
Password TAG
The passwords and keys are predefined by Philips Semiconductors by means of defined Transport
Passwords and a Transport Key. They can be written to, which means that they can be changed
(see also Chapter “Configuration of Delivered HITAG 2 Transponders“).
ATTENTION: Passwords and Keys only can be changed if their current values are known!