Hi All,
I need to write algorithm (to code later in C) for an embedded RFID device. I have a reader and a tag and I want to authenticate that the tag is an original one ( there is no need to authenticate the reader for the tag).
To do so the tags will have a secret number that is know in advance to the reader. The secret number will be put in manufacturing.
The authentication will be as follow:
- The reader will send a random number to the tag.
- The tag will do a certain algorithm with his secret number and the random number and will send the result to the reader.
- The reader will authenticate the return number and will send an ACK.
- The tag will then send is ID number, (The ID number is not the secret number, the secret number is never transmitted between the tag and the reader)
I need to fine a good and simple algorithm (for 8 bit microcontroller with low power) to do the work as describe in stage 2.
Any suggestion? Any useful links? Source code? BTW if you have a better scenario to achieve the authentication I'll be happy to read about.
Thanks in Advance Roy