ib technology

11

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

Block

0

0

0

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

User Data

End of memory

255 (FFh)

63 (3Fh)

15

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.

Data encryption option available

from Page 4 (Block 2) onwards

MSB 4-bytes (32 bit) LSB