Smartcard in CD

[Francois Grieu]

Michael Heyman wrote:
>But, how do they power it?


>From <http://www.doc-witness.com/>
>
>   An OPSECURE PROTECTED CD looks like a
>   regular CD but contains a smart card and
>   optical input-output system...
>
>   An OpSecure protected media does not
>   only reflect stamped or burnt information
>   but can also RECEIVE, STORE, PROCESS,
>   and TRANSMIT INFORMATION....


Other issues:

- How compatible can it be with the zillion different models of 
CD/DVD-R+RW/Unamit drives and drivers around ? This will make or 
break market acceptance. Together with the power source, this was a 
big problem with devices emulating floppies (using 3.5" drives as SC 
reader), which I helped design in the 90's.

- What can be the thruoutput of the drive-to-OpSecure link ? The only 
way I can think of transmitting info in this direction is by seeking 
to a slightly different location on the CD and several photodetectors 
on the OpSecure. Seek times will limit the bandwidth to few bits per 
second. Caches on the drive will get into the way to suppress head 
movements. Read-without-cache do not exist on any drive (much less 
driver) that I know, and retrofiting the drive firmware or even 
driver won't happen, so the cache may have to be flushed by reading a 
lot of other data, and this will further reduce bandwidth. On the 
other hand, very few bits need to be transmitted (especially in this 
direction) for copy-protection purposes.


I'd rather bet on single-chip USB Smart Cards.


   François Grieu

---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to majordomo at wasabisystems.com