[dm-crypt] Cryptographic issues with SSD-technology and wide-block encryption modes

Alex Elsayed eternaleye at gmail.com
Sat Feb 9 15:20:01 CET 2013

Stavros Kousidis wrote:

>> BTW anyone know what had happened with EME2 wide mode?
>> [snip long link]
> As far as I know there are intellectual-property issues:
> P. Rogaway, Block cipher mode of operation for constructing a
> wide-blocksize block cipher from a conventional block cipher, US Patent
> Application 20040131182 A1 _______________________________________________
> dm-crypt mailing list dm-crypt at saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt

Hey, this caught my attention so I contacted Dr. Rogaway. Included below is 
the email conversation (my apologies for the format, he replied at the top 
so I followed suit):


> Cool, thank you. It seems there was some misinformation in that thread 
> so would you mind if I quoted your response?

Go right ahead.

Best wishes,
Phil Rogaway

> On Friday, February 08, 2013 09:34:14 AM you wrote:
>> Hi Alex,
>>   There is no Rogaway or UC patent related to EME2.
>>   The University of California did do a patent application,
>>   but abandoned it (that is, decided not to pursue a utility patent).
>>   I had to look up some old correspondence to remind myself of this,
>>   but it seems that we informed Matt Ball and Jim Hughes back in Nov 2007
>>   that there'd be no patent, filling out some IEEE patent-disclosure
>>   form saying this, too.
>> Best wishes,
>> phil rogaway
>> On Fri, 8 Feb 2013, Alex Elsayed wrote:
>>> Hi, I was wondering if you had any plans to (explicitly) offer similar
>>> terms regarding open-source software for EME2 as you recently have for
>>> OCB. There was a recent discussion on the dm-crypt mailing list with the
>>> title "Cryptographic issues with SSD-technology and wide-block 
>>> modes." In the course of the discussion Milan Broz, the maintainer of
>>> dm-crypt, stated the following:
>>> "[It] would be nice to have some not patent encumbered wide mode (no 
>>> changes needed, just someone have to invent it and add to crypto API)"
>>> I'm just someone who reads the list, but I thought I'd write to point 
>>> that there's interest.
>>> (Frankly, I'm also very interested in OCB, but the other AE patents have
>>> an
>>> exceedingly unfortunate chilling effect independent of your license.)

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