Subject: Meaning of Non-repudiation

From: Dave Oshman <[email-masked]>
Date: Thu, 5 Apr 2001 12:23:55 -0400

I am trying to clarify the meaning of non-repudiation (as defined by the
technology standards) for our legal counsel. 2459 says this about
non-repudiation:
     The nonRepudiation bit is asserted when the subject public key is
      used to verify digital signatures used to provide a non-
      repudiation service which protects against the signing entity
      falsely denying some action, excluding certificate or CRL signing.

The question is what does "some action" mean? Is the action merely signing
the transaction? Or, is the action perhaps committing to the terms described
in the signed transaction?

To rephrase: Is non-repudiation stating simply that I, Dave Oshman, signed
this document? Or, is it supposed to mean that I, Dave Oshman, attest that I
am committing myself (or my company) to the terms described herein?

Is this more clearly defined in X.813 (ITU-T Recommendation X.8131) |
ISO/IEC 10181-3:...1), Information technology - Open Systems Interconnection
- Security Frameworks in Open Systems - Non-repudiation framework)? Can
anyone snip a description of non-repudiation from X.813?
Thanks!
Dave Oshman 
Senior Vice President 
Technology 
Identrus LLC

---

From: "Dr. JohnDavid Hascup" <[email-masked]>
Date: Thu, 5 Apr 2001 10:14:35 -0700

Meaning of Non-repudiationDave
  -----Original Message-----
  From: Dave Oshman [mailto:[email-masked]]
  Sent: Thursday, April 05, 2001 9:24 AM
  To: [email-masked]
  Subject: Meaning of Non-repudiation

  I am trying to clarify the meaning of non-repudiation (as defined by the
technology standards) for our legal counsel. 2459 says this about
non-repudiation:
  [JDH] this is the abyss of PKI. Having spent over three years working with
legal counsel on how to understand non-repudiation I have yet to find a
viable "legal" interpretation of the technological protocol. I think the
past year Tom Grindin was developing a "technical non-repudiation" draft
which I think has lapsed as of the past meeting in Minneapolis. It was an
attempt to ground non-repudiation with a meaning that would be "legal"
neutral but protocol specific.

  To rephrase: Is non-repudiation stating simply that I, Dave Oshman, signed
this document? Or, is it supposed to mean that I, Dave Oshman, attest that I
am committing myself (or my company) to the terms described herein?
  [JDH] IMO "legal" non-repudiation must be set via the entire environment
of the PKI as specifically defined in whatever policies the RP sets. This
means that it is the RP's use of the bit or non-use that is important. The
reason I felt this was due to the fact that once the question enters the
court it, the technical setting of the bit is not what is important but
rather the interpretation placed upon it by the RP and thus the EE. Apart
from a "clear stated policy" of what the RP intends for it's understanding
of non-repudiation the technical aspects are meaningless. The asserting of
the bit must be given meaning in the context of the environment and cannot
have a meaning legally apart from that environment. Therefore, your second
meaning can only be grounded in the policies set by the environment in which
you are signing and not in the technical underlying protocol. As for the
first, at most, one can argue that the cert granted to you signed. This is
why we had such a difficult time moving "technical" non-repudiation into a
legal context. What is the legal relationship between the certificate and
the person to whom the cert was issued. The protocol can offer forensic
evidence regarding the relationship and the actions of the cert but in and
of itself offers no legal meaning.

  Is this more clearly defined in X.813 (ITU-T Recommendation X.8131) |
ISO/IEC 10181-3:...1), Information technology - Open Systems
Interconnection - Security Frameworks in Open Systems - Non-repudiation
framework)? Can anyone snip a description of non-repudiation from X.813?

  Thanks!
  Dave Oshman
  Senior Vice President
  Technology
  Identrus LLC

  Dr. JohnDavid Hascup
  Senior Security Architect
  ELF Technologies

---

From: "Christopher S. Francis" <[email-masked]>
Date: Fri, 6 Apr 2001 09:06:27 -0400

Dr. Hascup,

It’s not clear to me why you feel that the policies of the RP regarding the
meaning of the non-repudiation bit are the primary factor in defining the
meaning of non-repudiation in that environment.  I’m not a lawyer, but it
seems to me that, although the RP’s policy plays a role, the primary
definition of what non-repudiation means in a particular environment should
come from the published policies of the signer.

If I sign something, shouldn’t my policy state whether a RP should interpret
my signature as an endorsement of the contents of whatever I signed?

Chris Francis

-----Original Message-----
From: Dr. JohnDavid Hascup [mailto:[email-masked]]
Sent: Thursday, April 05, 2001 1:15 PM
To: Dave Oshman; [email-masked]
Subject: RE: Meaning of Non-repudiation

Dave
-----Original Message-----
From: Dave Oshman [mailto:[email-masked]]
Sent: Thursday, April 05, 2001 9:24 AM
To: [email-masked]
Subject: Meaning of Non-repudiation
I am trying to clarify the meaning of non-repudiation (as defined by the
technology standards) for our legal counsel. 2459 says this about
non-repudiation:
[JDH] this is the abyss of PKI. Having spent over three years working with
legal counsel on how to understand non-repudiation I have yet to find a
viable "legal" interpretation of the technological protocol. I think the
past year Tom Grindin was developing a "technical non-repudiation" draft
which I think has lapsed as of the past meeting in Minneapolis. It was an
attempt to ground non-repudiation with a meaning that would be "legal"
neutral but protocol specific.
     The nonRepudiation bit is asserted when the subject public key is
      used to verify digital signatures used to provide a non-
      repudiation service which protects against the signing entity
      falsely denying some action, excluding certificate or CRL signing.
The question is what does "some action" mean? Is the action merely signing
the transaction? Or, is the action perhaps committing to the terms described
in the signed transaction?
To rephrase: Is non-repudiation stating simply that I, Dave Oshman, signed
this document? Or, is it supposed to mean that I, Dave Oshman, attest that I
am committing myself (or my company) to the terms described herein?
[JDH] IMO "legal" non-repudiation must be set via the entire environment of
the PKI as specifically defined in whatever policies the RP sets. This means
that it is the RP's use of the bit or non-use that is important. The reason
I felt this was due to the fact that once the question enters the court it,
the technical setting of the bit is not what is important but rather the
interpretation placed upon it by the RP and thus the EE. Apart from a "clear
stated policy" of what the RP intends for it's understanding of
non-repudiation the technical aspects are meaningless. The asserting of the
bit must be given meaning in the context of the environment and cannot have
a meaning legally apart from that environment. Therefore, your second
meaning can only be grounded in the policies set by the environment in which
you are signing and not in the technical underlying protocol. As for the
first, at most, one can argue that the cert granted to you signed. This is
why we had such a difficult time moving "technical" non-repudiation into a
legal context. What is the legal relationship between the certificate and
the person to whom the cert was issued. The protocol can offer forensic
evidence regarding the relationship and the actions of the cert but in and
of itself offers no legal meaning.