X-Git-Url: https://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/e704f8ad20e8ff15e8050eadfee243ae0ab777f3..d92811437f795412c6a59b7f3c2a78eacabfc8ea:/blog/index.rss diff --git a/blog/index.rss b/blog/index.rss index 5ece11a829..e42e39614e 100644 --- a/blog/index.rss +++ b/blog/index.rss @@ -6,6 +6,100 @@ http://people.skolelinux.org/pere/blog/ + + Idea for storing trusted timestamps in a Noark 5 archive + http://people.skolelinux.org/pere/blog/Idea_for_storing_trusted_timestamps_in_a_Noark_5_archive.html + http://people.skolelinux.org/pere/blog/Idea_for_storing_trusted_timestamps_in_a_Noark_5_archive.html + Wed, 7 Jun 2017 21:40:00 +0200 + <p><em>This is a copy of +<a href="https://lists.nuug.no/pipermail/nikita-noark/2017-June/000297.html">an +email I posted to the nikita-noark mailing list</a>. Please follow up +there if you would like to discuss this topic. The background is that +we are making a free software archive system based on the Norwegian +<a href="https://www.arkivverket.no/forvaltning-og-utvikling/regelverk-og-standarder/noark-standarden">Noark +5 standard</a> for government archives.</em></p> + +<p>I've been wondering a bit lately how trusted timestamps could be +stored in Noark 5. +<a href="https://en.wikipedia.org/wiki/Trusted_timestamping">Trusted +timestamps</a> can be used to verify that some information +(document/file/checksum/metadata) have not been changed since a +specific time in the past. This is useful to verify the integrity of +the documents in the archive.</p> + +<p>Then it occured to me, perhaps the trusted timestamps could be +stored as dokument variants (ie dokumentobjekt referered to from +dokumentbeskrivelse) with the filename set to the hash it is +stamping?</p> + +<p>Given a "dokumentbeskrivelse" with an associated "dokumentobjekt", +a new dokumentobjekt is associated with "dokumentbeskrivelse" with the +same attributes as the stamped dokumentobjekt except these +attributes:</p> + +<ul> + +<li>format -> "RFC3161" +<li>mimeType -> "application/timestamp-reply" +<li>formatDetaljer -> "&lt;source URL for timestamp service&gt;" +<li>filenavn -> "&lt;sjekksum&gt;.tsr" + +</ul> + +<p>This assume a service following +<a href="https://tools.ietf.org/html/rfc3161">IETF RFC 3161</a> is +used, which specifiy the given MIME type for replies and the .tsr file +ending for the content of such trusted timestamp. As far as I can +tell from the Noark 5 specifications, it is OK to have several +variants/renderings of a dokument attached to a given +dokumentbeskrivelse objekt. It might be stretching it a bit to make +some of these variants represent crypto-signatures useful for +verifying the document integrity instead of representing the dokument +itself.</p> + +<p>Using the source of the service in formatDetaljer allow several +timestamping services to be used. This is useful to spread the risk +of key compromise over several organisations. It would only be a +problem to trust the timestamps if all of the organisations are +compromised.</p> + +<p>The following oneliner on Linux can be used to generate the tsr +file. $input is the path to the file to checksum, and $sha256 is the +SHA-256 checksum of the file (ie the "<sjekksum>.tsr" value mentioned +above).</p> + +<p><blockquote><pre> +openssl ts -query -data "$inputfile" -cert -sha256 -no_nonce \ + | curl -s -H "Content-Type: application/timestamp-query" \ + --data-binary "@-" http://zeitstempel.dfn.de > $sha256.tsr +</pre></blockquote></p> + +<p>To verify the timestamp, you first need to download the public key +of the trusted timestamp service, for example using this command:</p> + +<p><blockquote><pre> +wget -O ca-cert.txt \ + https://pki.pca.dfn.de/global-services-ca/pub/cacert/chain.txt +</pre></blockquote></p> + +<p>Note, the public key should be stored alongside the timestamps in +the archive to make sure it is also available 100 years from now. It +is probably a good idea to standardise how and were to store such +public keys, to make it easier to find for those trying to verify +documents 100 or 1000 years from now. :)</p> + +<p>The verification itself is a simple openssl command:</p> + +<p><blockquote><pre> +openssl ts -verify -data $inputfile -in $sha256.tsr \ + -CAfile ca-cert.txt -text +</pre></blockquote></p> + +<p>Is there any reason this approach would not work? Is it somehow against +the Noark 5 specification?</p> + + + Når nynorskoversettelsen svikter til eksamen... http://people.skolelinux.org/pere/blog/N_r_nynorskoversettelsen_svikter_til_eksamen___.html @@ -544,33 +638,5 @@ available? Please send me an email if you know of any such tool.</p> - - Ruling ignored our objections to the seizure of popcorn-time.no (#domstolkontroll) - http://people.skolelinux.org/pere/blog/Ruling_ignored_our_objections_to_the_seizure_of_popcorn_time_no___domstolkontroll_.html - http://people.skolelinux.org/pere/blog/Ruling_ignored_our_objections_to_the_seizure_of_popcorn_time_no___domstolkontroll_.html - Mon, 13 Feb 2017 21:30:00 +0100 - <p>A few days ago, we received the ruling from -<a href="http://people.skolelinux.org/pere/blog/A_day_in_court_challenging_seizure_of_popcorn_time_no_for__domstolkontroll.html">my -day in court</a>. The case in question is a challenge of the seizure -of the DNS domain popcorn-time.no. The ruling simply did not mention -most of our arguments, and seemed to take everything ØKOKRIM said at -face value, ignoring our demonstration and explanations. But it is -hard to tell for sure, as we still have not seen most of the documents -in the case and thus were unprepared and unable to contradict several -of the claims made in court by the opposition. We are considering an -appeal, but it is partly a question of funding, as it is costing us -quite a bit to pay for our lawyer. If you want to help, please -<a href="http://www.nuug.no/dns-beslag-donasjon.shtml">donate to the -NUUG defense fund</a>.</p> - -<p>The details of the case, as far as we know it, is available in -Norwegian from -<a href="https://www.nuug.no/news/tags/dns-domenebeslag/">the NUUG -blog</a>. This also include -<a href="https://www.nuug.no/news/Avslag_etter_rettslig_h_ring_om_DNS_beslaget___vurderer_veien_videre.shtml">the -ruling itself</a>.</p> - - -