AW: LTANS: Examples of ERS data - cross checking of implementations

["Frei Adrian \(frr\)" <frr@xxxxxxxx>]

Hello,

Thomas Kunz wrote:
> >>>- How did the concatenation and hashing of the values in the
reduced
> >>>hash tree happen? When I concatenate the three values (51B1...,
> 5BD0...,
> >>>60BB...) in the first list in ascending order an hash them with
> >>>ripemd160, I get no value of the second list (B537..., 46D8...)
> 
> >
> > Are you (or Susanne) the one who wrote the implementation which
> > generated the evidence record or did you try to verify the record
with
> > your own implementation? My Problem is, that if I concatenate and
hash
> > the 3 values of the first level of the hash tree I don't get a value
of
> > the second level.
> >
> The procedure how to concatenate and hash the values in the reduced
> hashtree is decribed in section 3.3 of the I-D.
> You concatenate the three values (51B1..., 5BD0..., 60BB...) in the
> first list in ascending order an hash them with ripemd160. This hash
> becomes member of the second list (B537..., 46D8...). Now you
> concatenate these three hash values (the two in the list and the
> calculated one) and hash them, etc. Continue this procedure until the
> root hash is calculated. This root hash must correspond to the hashed
> message in the timestamp.
> 

Oh, stupid me. The "must become member of" and the fact that the digest
of the document is included in the hash tree must have confused me a
bit...

Well, thanks a lot; I was able to verify the first archiveTimeStamp.

Unfortunately I can't verify the whole evidence record; it seems that
the .NET cms implementation does only support md5 and sha1 as a hashing
algorithm. Might it be possible for one of you to provide an additional
ER/document-pair? 

Thanks,

Adrian

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