[cryptography] Dual_EC_DRBG was cooked, but not AES?

ianG iang at iang.org
Sun Sep 22 09:39:36 EDT 2013

On 22/09/13 16:05 PM, Ed Stone wrote:
> Why has AES escaped general suspicion? Are we to believe that NIST tested, selected, endorsed and promulgated an algorithm that was immune to NSA's toolset, without NSA participation and approval? NSA involvement in DES is known, but we await cryptanalysis or Snowdenesque revelations before having skepticism about AES?

NIST didn't really "test, select, endorse and promulgate" the AES 
algorithm, and neither did the NSA.

The process was a competition for open cryptographers, not agencies.  It 
was done this way because we strongly suspected DES interference.

Some 30 algorithms were accepted in the first round, and subject to a 
year or so worth of scrutiny by the same submitting teams.  This then 
led to a second round of 5 competitors and another long-ish period of 
aggressive scrutiny.  The scrutiny was quite fierce because the 
reputations of the winners would be made, so the 5 teams did their 
darndest to undermine the competition.  Many famous names were hoping 
for the prize.

It is the case that NIST (and probably the NSA) selected Rijndael from 
the 5 finalists.  But they did so on the basis of a lot of commentary, 
and all the critics was agreed that all 5 were secure [0].

So, claiming that the NSA perverted the AES competition faces a much 
higher burden.  They would have had to have done these things:

    * pervert some of the early teams,
    * pervert the selection process to enable their stooges through,
    * and designed something that escaped the aggressive scrutiny
      of the losers.

It's possible, but much harder to get away with.

In contrast, with the DRBG adventure, NSA designed the process, and 
tacked it onto a more internal NIST standards process.  Little or 
minimal scrutiny from outside, and little or minimal perversion of 
outsiders necessary in the standardisation phase (but that did come later).


[0]  At the time, myself and my team followed it, and we predicted that 
Rijndael would be the winner ... just by reading all the comments.  Note 
we weren't serious cryptographers, but we provided the Java framework 
for the competition, so it was a

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