Subject: Re: Alternatives for Long Term Archiving

From: Peter Sylvester <[email-masked]>
Date: Thu, 25 Mar 2004 22:08:15 +0100 (MET)

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> One of the ideas that came out of Seoul meeting (thanks to Larry Masinter)
> is to use a key-less approach to trusted archive.  The client who has vested
> interest in the secure storage of archived data, can use Shamir's n of m
> scheme to submit the archived data to m archive facilities.  m must be
> greater than 1 and should be selected based on availability needs. n must be
> greater than 1, less than or equal to m, and should be selected based on the
> desired degree of protection against collusion.
>  

Addressing the problem of confidentiality and redundancy need in this way
had been proposed as one of the work iteme of a research project
APRICOT concerning archiving. It seems useful to me to elaborate how
these aproach can be implemented in practice. 
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<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>One of the ideas 
that came out of Seoul meeting (thanks to Larry Masinter) is to use a key-less 
approach to trusted archive.&nbsp; The client who has vested interest in the 
secure storage of archived data, can use Shamir's n of m scheme to submit the 
archived data to m archive facilities.&nbsp; m must be greater than 1 and should 
be selected based on availability needs. n must be greater than 1, less than or 
equal to m, and should be selected based on the desired degree of protection 
against collusion.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN 
class=471225017-24032004></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>If this scheme is 
used, we may not need any cryptographic operations at the 
TAA.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN 
class=471225017-24032004></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>Under this scheme, 
the LTANS WG would need to still define various protocol for submission, 
deletion, and retrieval.&nbsp; if the idea is acceptable to the group, it could 
be the preferred or one of the approaches to perform 
archiving.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN 
class=471225017-24032004></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>As the current LTANS 
documents in the&nbsp;various stages state or imply, 
the&nbsp;trusted&nbsp;archive can continue to be used to submit any class of 
data.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN 
class=471225017-24032004></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>One advantage of the 
approach&nbsp;is that&nbsp;any&nbsp;document split is not sensitive even if the 
original document is sensitive.&nbsp; However, if the document requires 
confidentiality,&nbsp;assuming an adversary could be monitoring the channels to 
collect all the splits, the submission and retrieval of the split should be 
provided transmission security using techniques such as SSL or session 
encryption.&nbsp; This still is lot easier than needing to provide long-term 
encryption for stored data.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN 
class=471225017-24032004></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>To further 
illustrate one usage of the approach, a client with the&nbsp;need to provide 
long-term,&nbsp;non-repudiation of a transaction, could obtain current time 
stamp, all the trust anchor, certificates, revocation information relevant to 
signatures and time stamp, and package them using TBD record format and create m 
splits.&nbsp; These m split could be sent to m TAAs using TLS.&nbsp; Each TLS 
could provide a pointer to its split.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN 
class=471225017-24032004></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>When there is a need 
to retrieve the evidence, n splits could be retrieved from n TAAs that are 
available and can be combined to validate the signatures on the transaction as 
well as the time stamp.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN 
class=471225017-24032004></SPAN></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial size=2><SPAN class=471225017-24032004>The approach also 
offers some redundancy in case some TAAs are not available, data is corrupted, 
or the challenger does not trust some of the TAAs.</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT>&nbsp;</DIV><!-- Converted from text/rtf format -->
<P><SPAN lang=en-us><FONT face=Arial size=2>Santosh Chokhani</FONT></SPAN> 
<BR><SPAN lang=en-us><FONT face=Arial size=2>Orion Security Solutions, 
Inc.</FONT></SPAN> <BR><SPAN lang=en-us><FONT face=Arial size=2>1489 Chain 
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From: kent crispin <[email-masked]>
Date: Thu, 25 Mar 2004 13:35:13 -0800

On Thu, Mar 25, 2004 at 10:08:15PM +0100, Peter Sylvester wrote:

Hi Peter -- your mail client is sending strange attachments:

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-- 
Kent Crispin 
[email-masked]    p: +1 310 823 9358  f: +1 310 823 8649
[email-masked] SIP: [email-masked]