Re: problems with SHA-1
On Tue, 24 Jun 1997, Nathan E Norman wrote:
> On 25 Jun 1997, Mark Eichin wrote:
> :> IBM developed a cypher called "lucifer". The NSA examined it,
> :> recommended some changes to the algorithm, and the result was DES.
> :Changes which, we now know, *strengthened* it against differential
> :cryptanalysis (which they new about in the 70's, and called the
> :"sliding attack", if I remember Copperfield's comments correctly...)
> Yes and no ... they did weaken the S-boxes
> :> (Why did they approve it?? They *break* codes)
> :That's only one of their jobs. They're *also* in charge of *providing*
> :communications security to the government.
> ... but that doesn't include providing security to the public at large.
> Therefore, I stand by my statement, as it applies to you and me, not
> government agencies. I think recent events concerning cryptography
> export laws, key escrow, clipper, etc. strengthen rather than reduce my
A few points. When the cryptography export laws were originally made, the
US was far ahead of any other country in encryption research, that has now
changed. Also, when the decision was made to try to restrict it's
exportability, the decision was made because people were asked, "what
technology of ours, do we want to keep out of our enemies hands",
encryption was one of those things.
On the clipper issue, clipper, IMO, wasn't so bad, except if it also
outlaws other encryption. If my telephone would include clipper by
default, that would be good. Why? Yes the NSA or the govt. could tap into
my phone, but they can do that now. clipper would prevent joe cracker
from tapping my phone or the like. And if I don't want NSA to crack my
telephone conversation, I use something like pgpfone over it.
> :> Also, DES is not approved by the government for internal use if the
> :> security level is Top Secret or above (if memory serves correctly).
> :Nope; it's actually not approved for *any* classification level. NSA
> :supplies special tools and keying material for classified data
> :handling. DES was for *commercial* and *personal* data...
> My mistake. I looked this up and you're 100% correct :)
> :> Strange that the government recommends that businesses use a cypher they
> :> don't use, don't you think?
> :Nope; as far as is publically known, for classified material they only
> :ever approved *hardware* solutions. (In the original DES spec, a
> :"correct" implementation had to be in hardware; certification of
> :software implementations came maybe 10 years later...) Of course, we
> :only know this after 20+ years of scrutiny and analysis, and that
> :doesn't help us judge the *current* political situation.
> You really don't answer the question, in spite of the "nope".. *Why*
> does the government insist that the business and personal communities
> trust an algortihm that thay themselves don't use? Doesn't that display
> an implicit mistrust? If I sold you software that I wrote but refused
> to let my employees use it, wouldn't you find that odd?
The government uses highly secure operating systems, some of them are very
anal, does that mean business and the personal communities should use them
too. No, just because the government doesn't use something doesn't mean
it isn't secure. If it wasn't secure they would say don't use it all, but
their are some uses for it in the government.
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