[mailto:owner-ietf-smime(_at_)mail(_dot_)imc(_dot_)org] On Behalf Of Denis
Sent: Thursday, August 24, 2006 11:29 AM
Subject: Re: I-D ACTION:draft-ietf-smime-escertid-01.txt
In order to solve my two concerns, the faster is to propose a
I hope this will clarify my statements.
The statement in the parenthesis is not true. The
issuer/serial number is not sufficient.
I propose the following as a global replacement:
The issuer/serial number pair is the method of identification of
certificates used in [PKIXCERT]. The issuer/serial number pair may
be insufficient since two or more CAs with the same DN
could exist in different branches from a given certification tree. The
issuer/serial number pair may be used as a hint to fetch the
certificate(s). The issuer/serial number pair can be stored in the
sid field of the SignerInfo object. In the cases where the
issuer/serial number pair is not used in the sid, it should be
placed in the issuerSerial field of the ESSCertIDv2 structure.
In some cases, hashes are used by certificate stores as a method of
indexing and retrieving certificates, hence another reason for
having the issuer/serial number pair optional.
The hash of the entire certificate allows for a verifier to check
that the certificate used in the verification process is indeed the
one the signer intended to be used. The use of the hash is
required by this structure since the detection of substituted
certificates with the same DN and serial number is based on the
fact they would map to different hash values.
I have several problems with draft-ietf-smime-escertid-01.txt.
In RFC 2634, we have section "5.4 called Signing Certificate
The proposal is to add a section 5.4.1 to define the v2 version
first (!) and then the current version (with SHA-1).
This should be done in the reverse way:
- first a section 5.4.1 to define the current version (with SHA-1),
- then a section 5.4.2 to define the v2 version.
I prefer the existing ordering. I would rather have the
items that people are to be using occur first and then
obsolete items rather than the other way around. I have not
After this restructuring, I have some problems with the
text itself :
Issue 1 (page 4):
"Applications SHOULD recognize both attributes as long as
they consider SHA-1 to be sufficiently descriminating".
"descriminating" is not crystal clear for me. Would it be
to have the same idea expressed using a different wording ?
Issue 2 (pages 4 & 5):
There is a duplication of the same paragraph (one is enough):
"The signing certificate attribute is designed to prevent the
substitution and re-issue attacks, and to allow for a
of authorization certificates to be used in verifying a
I believe that not having any descriptive text at these
locations and jumping directly into the ASN.1 to be a poor
choice. I have not changed this.
Issue 3 (page 7):
"The issuer/serial number pair would therefore normally be
to identify the correct signing certificate. (This assumes the
issuer name is not re-used from the set of trust anchors.)"
The assumption between the parenthesis is insufficient to
identify the correct signing certificate. The sentence needs to be
I do not understand your statement. If the statement in
parenthesis is true, then it is sufficent. If the statement
in the parenthesis is not true, then issuer/serial number is
not sufficent. Please re-read the text and explain better
what your problem is.
Issue 4 (page 7):
"In the cases
where the issuer/serial number pair is not used in the sid or the
issuer/serial number need to be signed, they should be
issuerSerial field of the ESSCertIDv2 structure."
The issuer/serial number pair can be used in the sid, but
is unsigned, it is insufficient to correctly identify the correct
So this rational is incorrect. The sentence needs to be changed.
I have no idea what you are trying to state here. My
sentence and your comment do not seem to be coming from the
same context. Please re-read the sentence.
Finally, I would propose that the next draft proposes a global
replacement for section 5.4 to make sure that the whole section is
consistent (and that the text in it is not redondant).
I can understand your concern, however I believe that the
current layout is better and more explicit for the RFC editor.
>A New Internet-Draft is available from the on-line
>This draft is a work item of the S/MIME Mail Security
of the IETF.
> Title : ESS Update: Adding CertID
> Author(s) : J. Schaad
> Filename : draft-ietf-smime-escertid-01.txt
> Pages : 18
> Date : 2006-4-18
>In the original Enhanced Security Services for S/MIME draft, a
structure for cryptographically linking the certificate to
be used in
validation with the signature was introduced, this structure was
hardwired to use SHA-1. This document allows for the
have algorithm agility and defines new attributes to deal
>A URL for this Internet-Draft is:
>To remove yourself from the I-D Announcement list, send a
i-d-announce-request(_at_)ietf(_dot_)org with the word unsubscribe in
of the message.
>You can also visit
>to change your subscription settings.
>Internet-Drafts are also available by anonymous FTP.
Login with the
username >"anonymous" and a password of your e-mail address. After
logging in, >type "cd internet-drafts" and then
> "get draft-ietf-smime-escertid-01.txt".
>A list of Internet-Drafts directories can be found in
>Internet-Drafts can also be obtained by e-mail.
>Send a message to:
>In the body type:
> "FILE /internet-drafts/draft-ietf-smime-escertid-01.txt".
>NOTE: The mail server at ietf.org can return
the document in
> MIME-encoded form by using the "mpack" utility. To use this
> feature, insert the command "ENCODING mime" before
> command. To decode the response(s), you will need
> a MIME-compliant mail reader. Different MIME-compliant
> exhibit different behavior, especially when dealing with
> "multipart" MIME messages (i.e. documents
which have been
> up into multiple messages), so check your local
> how to manipulate these messages.
>Below is the data which will enable a MIME compliant mail reader
implementation to automatically retrieve the ASCII version of the