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From: Tom St Denis on 1 Apr 2010 08:43
On Apr 1, 8:04 am, Thomas Pornin <por...(a)bolet.org> wrote:
> According to Wolfgang Ehrhardt <W...(a)completely.invalid>:
>
> > I just downloaded your source and tested my own bit api functions with
> > your test cases from the test_sha1/2/3.c files. Are the test vectors
> > other than the well-known "abc" etc from other sources or do you have
> > calculated them for reference and/or regression tests?
>
> The test vectors I use are from FIPS 180-3 (the "abc" etc) and from RFC
> 4634 (some of them have a length not multiple of 8). Note that only my C
> code can deal with inputs which are not an integral number of bytes; my
> Java code cannot do that (yet).

Although I see the appeal of handing any message length I have yet to
actually see an application radio, physical link, or otherwise that
actually transmits non-multiples of 8 units (on quantities that would
be HMAC'ed anyways, I realize that certain radio frames can be
arbitrary sized).

Tom
From: David T. Ashley on 6 Apr 2010 17:33
"Wolfgang Ehrhardt" <WE(a)completely.invalid> wrote in message
news:4bb3a551.8475080(a)news.individual.net...
> On Tue, 30 Mar 2010 17:23:30 -0400, "David T. Ashley"
> <dashley(a)gmail.com> wrote:
>
>>I implemented FIPS 180-3 (I'm not really a competent Windows programmer).
>>
>>You can find the executable here:
>>
>>http://www.s-512.com/filehash.exe
>>
>>and the source code here:
>>
>>http://www.s-512.com/filehash.zip
>>
>>Anyway, I will review the code carefully in the next few days, and do some
>>unit tests (boundary cases, etc.).
>>
>>But if anyone wants to beat it around and tell me if it seems correct ...
>>I'd be grateful.
>
> The description on you web page seems (due to some fuzzyness of spoken
> language) to confuse collision resistance with (second) preimage
> resistance:
>
> "The mathematics of a birthday attack suggest that 1.6�10^74 guesses
> would be required to obtain even a one-in-a-million probability of
> finding a file with the same cryptographic hash.
>
> Using 10 billion computers that each could calculate 10,000 hashes per
> second (both very optimistic assumptions), to get a one-in-a-million
> probability of finding another file with the same SHA-512 hash would
> require 5�10^52 years."

Thanks for that. I caught that independently, and just made a second post
to sci.math and sci.crypt.

It was just by chance that I found your post, which is stated more elegantly
than the post I just made.

Perhaps you can answer my expected value question in the recent post ...

Thanks, Datesfat

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