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RE: [ers-02.txt] Questions
Ok then, it's all clear to me now.
Thanks a lot for spending time to explain.
Best regards,
Loïc
> -----Message d'origine-----
> De : Tobias Gondrom [mailto:tgondrom@xxxxxxxxxxxx]
> Envoyé : vendredi 29 avril 2005 18:11
> À : HOUSSIER Loic RD-MAPS-ISS
> Cc : ietf-ltans@xxxxxxx; A. Jerman Blazic
> Objet : RE: [ers-02.txt] Questions
>
> Loïc,
>
> Maybe to provide further info:
>
> > Well, it's more clear to me now...
> > ERS just proposes a syntax for EV that can be used by CSM to kepp
> > electronic signature valid.
> > But according to RFC-3126, ES-A is a format that reech the
> same target
> > than ERS in CMS.
>
> Yes. In some way ES-A in RFC3126 is trying to achieve the same.
> With ES-A you can try to "re-sign" a signed file with a new
> layer wrapped around it every time a cryptographic algorithm
> gets weak (respectively before) - the concept is quite
> obvious and well thought for the use case to store only a
> limited number of signed documents.
>
> As Aleksej already described ERS also enables the possibility
> for long-term non repudiation and integrity.
> Second aspect of ERS is that it scales for large volumes of
> signed documents. With ES-A you have to wrap around every
> file another layer.
> With ERS you just create new hashtrees - which is if you
> think of e.g. about 10^6 to 10^9 documents a lot better
> concerning performance. (especially if only e.g. a public key
> algorithm gets weak or a used key length is no longer sufficient.)
>
> Concerning RFC3126: From my opinion it is not necessary that
> ERS will obsolete ES-A. But I surely expect that many big
> storage, Document Management System and ECM vendors will
> implement ERS and not ES-A. So in B2B and B2C we will most
> probably seeing a lot of ERS.
>
> The coexistence of ES-A and ERS will be something to discuss
> when ERS is finally an RFC.
>
> Best regards
>
> Tobias
>
>
>
>
>
> >
> > So my question is, if i want to archive signature, i have the choice
> > between RFC3126 ES-A or ERS in CMS. Am I right ?
> >
> > If I am, will ES-A be obsoleted by ERS in CSM (as shown in
> Appendix A in
> > [ers-02]) ?
> >
> > But be sure that I understand ERS is more than just a way
> to maintain a
> > singature valid.
> >
> > Regards,
> >
> > Loïc
> >
> >
> >
> > > -----Message d'origine-----
> > > De : A. Jerman Blazic [mailto:aljosa@xxxxxxxxx]
> > > Envoyé : vendredi 29 avril 2005 11:48
> > > À : HOUSSIER Loic RD-MAPS-ISS; ietf-ltans@xxxxxxx
> > > Objet : RE: [ers-02.txt] Questions
> > >
> > > Loic
> > >
> > > This is what I didn't state. You have to distinguish the
> > > level of the two
> > > approaches. ERS deals mainly with providing syntax on (time)
> > > evidence and
> > > evidence on integrity of a data, while RFC3126 provides data
> > > strucutre for
> > > long term validity of a digital signatures. In this case RFC
> > > can rely on ERS
> > > for time and integrity evidence of a signature, so it is a
> > > more low level
> > > syntax. Or in other words, if you equip CMS with accredited
> > > time, you can
> > > ged basic ERS structure (of course ERS is more than that:
> > > e.g. grouping and
> > > hash trees). This is why I said the approaches of LTANS
> vs. XAdES are
> > > somehow different, while addressing similar problems.
> > >
> > > BR
> > >
> > > Aleksej
> > >
> > > > -----Original Message-----
> > > > From: HOUSSIER Loic RD-MAPS-ISS
> > > > [mailto:loic.houssier@xxxxxxxxxxxxxxxxx]
> > > > Sent: 29. april 2005 11:24
> > > > To: A. Jerman Blazic; ietf-ltans@xxxxxxx
> > > > Subject: RE: [ers-02.txt] Questions
> > > >
> > > > Aleksej,
> > > > Thanks for your reply.
> > > >
> > > > So, to demonstrate the existantce and stability of signature
> > > > on particular, there will be two ways in PKIX community:
> > > > One using rfc3126, one with ERS attribute within a CMS
> > > > signature object. Am I wrong ?
> > > >
> > > > Loïc
> > > >
> > > >
> > > >
> > > > > -----Message d'origine-----
> > > > > De : A. Jerman Blazic [mailto:aljosa@xxxxxxxxx] Envoyé :
> > > > vendredi 29
> > > > > avril 2005 11:08 À : HOUSSIER Loic RD-MAPS-ISS;
> > > ietf-ltans@xxxxxxx
> > > > > Objet : RE: [ers-02.txt] Questions
> > > > >
> > > > > Dear Loic
> > > > >
> > > > > I would be very careful here. XAdES for example is like the
> > > > name says:
> > > > > syntax for extended signature, which builds on top of a
> > > > signature and
> > > > > includes all needed complementary data to provide long term
> > > > stability
> > > > > of digital signatures. The LTANS position, as I understand it,
> > > > > distances from such approach and deals with long term
> > > stability of
> > > > > data. ERS in this case defines requirements on how to
> > > > demonstrate the
> > > > > existence and stability of data (not signature on
> > > particular) on a
> > > > > timeline. It does not define the data structure nor the
> > > > syntax and at
> > > > > the moment you can freely use any interpretation of an
> > > > evidence record
> > > > > including CMS. But XAdES? I am not so sure....
> > > > >
> > > > > Best regards
> > > > >
> > > > > Aleksej
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: owner-ietf-ltans@xxxxxxxxxxxx
> > > > > > [mailto:owner-ietf-ltans@xxxxxxxxxxxx] On Behalf Of
> > > HOUSSIER Loic
> > > > > > RD-MAPS-ISS
> > > > > > Sent: 29. april 2005 10:46
> > > > > > To: ietf-ltans@xxxxxxx
> > > > > > Subject: [ers-02.txt] Questions
> > > > > >
> > > > > >
> > > > > > Hi all,
> > > > > >
> > > > > > Reading ERS_02, I have question :
> > > > > > It s said that ER can be part of the Archive or can be
> > > stored as
> > > > > > another file. What I understand is that we can (using CMS
> > > > or XADES)
> > > > > > do ER as part of the Archive.
> > > > > > But Is it compliant with ERS ?
> > > > > >
> > > > > > Thanks
> > > > > >
> > > > > > Loïc
> > > > > >
> > > > > >
> > > > > >
> > > > > > > -----Message d'origine-----
> > > > > > > De : owner-ietf-ltans@xxxxxxxxxxxx
> > > > > > > [mailto:owner-ietf-ltans@xxxxxxxxxxxx] De la part de
> > > > > > > Internet-Drafts@xxxxxxxx Envoyé : vendredi 8 avril 2005
> > > > 21:29 À :
> > > > > > > i-d-announce@xxxxxxxx Cc : ietf-ltans@xxxxxxx Objet : I-D
> > > > > > > ACTION:draft-ietf-ltans-ers-02.txt
> > > > > > >
> > > > > > > A New Internet-Draft is available from the on-line
> > > > > Internet-Drafts
> > > > > > > directories.
> > > > > > > This draft is a work item of the Long-Term Archive and
> > > > > > Notary Services
> > > > > > > Working Group of the IETF.
> > > > > > >
> > > > > > > Title : Evidence Record Syntax (ERS)
> > > > > > > Author(s) : R. Brandner, et al.
> > > > > > > Filename : draft-ietf-ltans-ers-02.txt
> > > > > > > Pages : 25
> > > > > > > Date : 2005-4-8
> > > > > > >
> > > > > > > In many scenarios, users need to be able to ensure and
> > > > prove the
> > > > > > > existence and integrity of data, especially digitally
> > > > > > signed data,
> > > > > > > in
> > > > > > > a common and reproducible way over a long and possibly
> > > > > > undetermined
> > > > > > > period of time. This document specifies the syntax and
> > > > > > processing
> > > > > > > of
> > > > > > > an Evidence Record, designed for long-term
> > > > non-repudiation of
> > > > > > > existence of data, which particularly can be used for
> > > > > > conservation
> > > > > > > of
> > > > > > > evidence of digitally signed data.
> > > > > > >
> > > > > > > A URL for this Internet-Draft is:
> > > > > > >
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