Re: Stream Cipher Like SEAL Wanted ....

From: Mrsjunecarey (mrsjunecarey_at_aol.com)
Date: 06/21/03 

Date: 21 Jun 2003 11:20:53 GMT

>This is fine in theory. But in practice you must, to some extent or
>other, depend on assumptions that you're meeting the requirements for
>OTP security. I don't see these as being particularly different from
>assuming that well-studied cryptographic primitives are secure.

But they are different. OTP is gauranteed secrecy and ECC isn't.

>I can see that working really well.

Heh :)
When designing such a system one would choose a suitably large size of memory
for the OTP to cover all possible situations.

You could also provide an emergency back-up system that uses some non-provably
secure cryptosystem.

Or in an emergency you could just start reusing your pad (not a good idea :).

>The problem is how to ensure that your CD or whatever is only ever
>inserted into the right kind of secure crypto module. The obvious
>answer to this problem -- encrypt the data -- doesn't work. And CDROMs
>are hard to erase piecemeal.

Well one idea might be to have some code that has to be entered before the OTP
can be used. And if the wrong code is entered three times in a row you delete
the OTP
and render the system unusable.

I imagine a CDROM could be erased quickly with a pyrotechnic solution :)

>
>-- [mdw]