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RE: FW: comments on <draft-ietf-spki-cert-theory-02.txt>
Micheal, I now understand what this list is about. I will make the point
that when you as a co chair and the chair of a list put a document into
the public domain, which has major illogical and misleading content then
be prepared for the comments. Particularly when you denegrate an
essential technology which is being deployed globally. If you think
document is of good quality, good reasoning and good engineering which
includes operational pragmatism , that is your view. Its not mine.
Theory is about religion, Engineering is about reality.
From: Michael C. Richardson
To: Alan Lloyd
Sent: 7/27/98 9:35:14 AM
Subject: Re: FW: comments on <draft-ietf-spki-cert-theory-02.txt>
>>>>> "Alan" == Alan Lloyd <Alan.Lloyd@OpenDirectory.com.au> writes:
Alan> Let me explain something to this list which seems to be
Alan> A certficate is a digital form of ones key, ones identity and
Alan> privileges within a domain as defined by the key issuer of
That is an X.500-type definition.
[I refrain from calling it an X.509v3-type definition since I know
X.509v3 has gotten over this as well.]
SPKI rejects the X.500-type definition and says that a certificate is
something authorizes some verifier defined action. The exact text is
The term certificate traces back to the MIT bachelor's thesis of
Loren M. Kohnfelder [KOHN]. Kohnfelder, in turn, was responding to a
suggestion by Diffie and Hellman in their seminal paper [DH]. Diffie
and Hellman noted that with true public key cryptography, one no
longer needs a secure channel over which to transmit secret keys
between communicants. Instead, one can publish a modified telephone
book -- one with public keys in place of telephone numbers. Diffie
and Hellman went on to propose that such a directory could be on-line
and maintained by a trusted source. One could then look up his or
her desired communication partner in the directory, find that
person's public key and open a secure channel to that person.
Kohnfelder took that suggestion and noted that an on-line service has
the disadvantage of being a performance bottleneck. To replace it,
he proposed creation of digitally signed directory entries which he
called certificates. In the time since 1978, the term certificate
has frequently been assumed to mean a binding between name and key.
The SPKI team directly addressed the issue of <name,key> bindings and
realized that such certificates are of extremely limited use for
trust management. A keyholder's name is one attribute of the
keyholder, but as can be seen in the list of needs in this document,
a person's name is rarely of security interest. A user of a
certificate needs to know whether a given keyholder has been granted
some specific authorization.
If you don't accept this point, then SPKI isn't for you, end of
:!mcr!: | Network and security consulting/contract
Michael Richardson | Firewalls, TCP/IP and Unix
ml">email@example.com</A>. PGP key available.
ON HUMILITY: To err is human, to moo bovine.