[Ndn-interest] Interest Signature

[Mosko, Marc <mmosko@parc.com>]

(Due to a change at PARC, my current email address was not a subscriber to this list, so I had to cancel and re-post this message).

Out of curiosity, I looked through the Gerrit on the new signed interest.  I do like this direction better than the old signed interest where it is all munged in the name.

I noticed at the end of the code review comments there is the statement "The signature should not cover Name-TYPE and Name-Length."  I did not see it in the comments, but I assume you are applying the same logic to the Parameters and SignatureInfo fields?

I think that is not correct.  When computing a digest over multiple fields, you need to delimit those fields somehow (a special character or length encoding, etc.).  Otherwise, you could have a first field with the values of the later fields and the later fields empty and get the same digest and thus the same signature.  For example, if my digest is over fields A and B, if I do not delimit them, I could have A="abc" and B="def" or A="abcdef" and B="" and they would look the same.

I think this sentence is confusing.  Maybe use more commas or break it up or use set notation.

>>> The cryptographic signature that is included in the ``InterestSignatureValue`` element covers all bytes of the ``Name`` element excluding the ``ParametersSha256Digest`` component, the Parameters element if presents, and the SignatureInfo.

It could be read that the signature _excludes_ the Parameters and SignatureInfo.  You also use "bytes" and then "component" which mixes measurements.

So it appears that the signature is only on the tuple (Name \  ParametersSha256Digest, Parameters, SignatureInfo).  Usually one would makes those contiguous memory to simplify the digest calculation, so I would have expected the BNF to have Parameters and SignatureInfo directly after Name, assuming that the BNF implies normal ordering.


Marc

________________________________________
From: Ndn-interest <ndn-interest-bounces at lists.cs.ucla.edu> on behalf of Zhiyi Zhang <Zhiyi.Zhang at ucla.edu>
Sent: Saturday, January 12, 2019 11:35:33 AM
To: 侯 ?博
Cc: mini-ndn at lists.cs.ucla.edu; ndn-interest at lists.cs.ucla.edu
Subject: Re: [Ndn-interest] Interest Signature

Actually, we have a pending commit waiting to be merged into NDN-TLV specification: https://gerrit.named-data.net/c/NDN-TLV/+/4942
This commit defines the new NDN Signed Interest format.
Also, there is a corresponding implementation in ndn-lite library: https://github.com/named-data-iot/ndn-lite/blob/master/encode/signed-interest.h and https://github.com/named-data-iot/ndn-lite/blob/master/encode/signed-interest.c.

Hope it helps.

Best,
Zhiyi

On Fri, Jan 11, 2019 at 8:20 PM 侯 ?博 via Ndn-interest <ndn-interest at lists.cs.ucla.edu<mailto:ndn-interest at lists.cs.ucla.edu>> wrote:
Hello all,
I want to add signature for Interest packet. So I do some actions as follow:
Firstly, I add a member named m_signature in Interest.hpp.
Secondly, I add set and get function for this field of m_signature in interest.hpp.
Thirdly, I change the function of wireEncode and wireDecode in interest.cpp to encode and decode it.
Finally, I  add a value for m_signature  in ndn-consumer.cpp.
However, when I run the test program of ndn-simple,it shows the folloing errors，is there anyone can help me to resolve it.

terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<ndn::Interest::Error> >'
what():  unrecognized element of critical type 4294967295

Thanks a lot.


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