RWD_QT Datasheet, PDF (11/19 Pages) rfsolutions.ltd – The MicroRWD “QT” (Quad-Tag) version is a complete 125kHz reader solution for Hitag 1,

ib technology
Encryption Methodology
The Micro RWD H1/S has a data encryption system that allows data to be stored in an
encoded form that cannot be read as sensible data by any other Hitag 1 reader system.
The format of the data stored in the transponder memory (apart from the serial number,
configuration and other data in Pages 0 - 3) is controlled by the Encryption Control byte in the
Micro RWD internal EEPROM. If Encryption Control ON is selected then all data stored in
the transponder from page 4 upwards will be encrypted, and if OFF is selected then all data is
stored in standard format.
The method of encryption uses a “dynamic algorithm” which effectively makes the encoded
data specific to a particular transponder and a set of encryption seed values stored in the
Micro RWD internal EEPROM. This not only protects stored information but also prevents
cloning of cards or copying of data. Information is encrypted when being stored and
decrypted when being read, thereby making the process totally transparent to the user.
Another Hitag 1 reader system would read encrypted data as random bytes with no meaning.
Users should program their own encryption seed values to fully customise their system.
Hitag 1 Memory Map
Byte
Page
0
0
MSB 4-bytes (32 bit) LSB
Block
0
Data encryption option available
from Page 4 (Block 2) onwards
Serial number (Page 0)
Config’ bytes (Page 1)
(Reserved Memory)
64 (40h) 16 (10h) 4
User Data
128 (80h) 32 (20h) 8
User Data
192 (C0h) 48 (30h) 12
End of memory
255 (FFh) 63 (3Fh) 15
User Data
Hitag 1 transponders have Pages 16 to 63 available for user data storage (192 bytes). It is
advised not to use the memory locations below page 16 because these are used for
configuration bytes and a “Reserved” memory area.
Hitag S transponders configured in PLAIN MEMORY mode have a similar memory map to
Hitag 1 except they have available “user data ” memory from Page 2 onwards. Hitag S256
transponders therefore have Page 2 – 7 (24 bytes) for user data and Hitag S2048 types have
Page 2 - 63 (248 bytes) for user data.
11