[Cryptography] RFID Protocols

[John Denker]

On 10/02/2015 02:36 PM, Ryan Carboni wrote:

> A google search yields nothing for RFID protocols.

I get 21,000 hits from
  https://www.google.com/search?q=%22rfid+standards%22#q=%22rfid+protocols%22

and 37,000 hits from
  https://www.google.com/search?q=%22rfid+standards%22

More specifically, we have standards including:
  http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=46145
  http://www.iso.org/iso/home/store/catalogue_ics/catalogue_detail_ics.htm?csnumber=61128
  http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=67412

>  So I'm going here to ask
> the following questions:
> Can an RFID chip contain a store of entropy (meaning must a lightweight
> cipher be secure against known and chosen key attacks)?

Some of them yes, some of them no.
 
> How does an RFID protocol prevent replay attacks?

Some of them do, and some of them don't.

The term "RFID" covers a lot of territory.  Technically speaking,
at the high end it covers military IFF systems, which have every
advanced feature you can think of.  At the low end, they are
smaller than a dust mote, and have no more intelligence than
a bar code ... a completely open code, with no replay resistance
whatsoever.

See also:
  https://en.wikipedia.org/wiki/Radio-frequency_identification