Re: XML DSIG Algorithm URNs

Given the suspicious things that have been found re MD5, I think that
if we included it, we would have to specifcially recommend against its
use with RSA or similar signature algorithms. (As far as I know these
suspicious things do not effect its security in HMAC applications.)

However, given the state of standardization of XMLDSIG and the large
number of possible additional URNs, I think it would be a better idea
to have an additional supplemental document for them.  What do people
think of such an idea?

Thanks,
Donald

From:  "Joseph Ashwood" <jashwood@arcot.com>
Message-ID:  <035d01c0bd3b$bbf04620$2a0210ac@livermore>
To:  <w3c-ietf-xmldsig@w3.org>
References:  <OF053FCE02.426B57FA-ON85256A24.0015A56B@somers.hqregion.ibm.com>
Date:  Wed, 4 Apr 2001 12:15:30 -0700

>The desire for RIPEMD series hashs is extremely rare, or least has been in
>my experience. It has been my experience that at the various sizes the
>preferred algorithms are MD5 (128), SHA-1 (160), Tiger-192, SHA-256,
>SHA-384, SHA-512, very few people seem to even consider going larger than
>SHA-512. So I don't think there's any real need to create a unified
>directory of any more than those. Recently I've noticed an increase of
>desire for hash mode cipher functions, so we may want to consider having at
>least token support for them, I personally don't appreciate them, I have
>generally found that they are easier to attack, or at least as slow as a
>dedicated hash function, but some people swear by them (although I do admit
>I appreciate some of the provable aspects of them). Personally I'd say we
>should include those before we go about including RIPEMD, Whirlpool, etc,
>simply because it is more likely that someone will desire them (although in
>the next few years Whirlpool will probably be named the Cryptonessie hash
>function, so it may come into demand).
>                                        Joe
>----- Original Message -----
>From: "Tom Gindin" <tgindin@us.ibm.com>
>To: "Glenn Adams" <gadams@vgi.com>
>Cc: "Brian LaMacchia" <bal@microsoft.com>; <w3c-ietf-xmldsig@w3.org>
>Sent: Tuesday, April 03, 2001 9:00 PM
>Subject: Re: XML DSIG Algorithm URNs
>
>
>>
>>      Brian's point about defining URN's for the new extended SHA's is
>still
>> appropriate, even assuming that we include support for MD5 and RSA/MD5.
>> Should we include RIPEMD-160 (and perhaps RIPEMD-128) as well?  They are
>> not mandatory to implement, of course.
>>
>>           Tom Gindin
>>
>>
>> "Glenn Adams" <gadams@vgi.com>@w3.org on 04/03/2001 08:35:59 PM
>>
>> Sent by:  w3c-ietf-xmldsig-request@w3.org
>>
>>
>> To:   "Brian LaMacchia" <bal@microsoft.com>
>> cc:   <w3c-ietf-xmldsig@w3.org>
>> Subject:  Re: XML DSIG Algorithm URNs
>>
>>
>> We are also using SHA-1 (and recommend it as a preference), but need to
>use
>> MD5
>> for compatibility with certain existing practice as well; that is, we have
>> certain legacy issues we must contend with. It seems to us that XML DSIG
>> should
>> recognize the continued use of these legacy algorithms even if they are
>not
>> recommended.
>>
>> Regards,
>> Glenn
>>
>> ----- Original Message -----
>> From: "Brian LaMacchia" <bal@microsoft.com>
>> To: "Glenn Adams" <gadams@vgi.com>
>> Cc: <w3c-ietf-xmldsig@w3.org>
>> Sent: Tuesday, April 03, 2001 12:52 PM
>> Subject: RE: XML DSIG Algorithm URNs
>>
>>
>> > We didn't define URLs for MD5 because the crypto community has moved
>> > away from using or recommending MD5 in any new standard over the past
>> > few years, and thus there wasn't anyone pushing for use of MD5 with
>> > XMLDSIG.  Why are you specifying use of MD5 in a new standard?
>> > Shouldn't you be using at least SHA-1?  Along these lines, the request I
>> > expected to see is for XMLDSIG to specify URLs for SHA-256, SHA-384 and
>> > SHA-512.
>> >
>> > Note: I'm not saying we shouldn't specify an URL for MD5 and
>> > RSA-MD5-PKCS1v1.5, just questioning your reliance on it in a new
>> > standard.  However, if we are going to open up the URL list then we
>> > should definitely add SHA-256, -384 and -512 to the list.
>> >
>> > --bal
>> >
>> > -----Original Message-----
>> > From: Glenn Adams [mailto:gadams@vgi.com]
>> > Sent: Monday, April 02, 2001 6:11 PM
>> > To: w3c-ietf-xmldsig@w3.org
>> > Subject: XML DSIG Algorithm URNs
>> >
>> >
>> > The ATSC (Advanced Television Systems Committee) DASE (DTV Application
>> > Software
>> > Environment) is expected to normatively reference the XML DSIG
>> > recommendation (hopefully to be finalized very soon).
>> >
>> > It is a requirement of DASE to support MD5 as a message digest algorithm
>> > as well as MD5 with RSA Encryption as a signature algorithm, and thus we
>> > need URNs to refer to these algorithms. We note that XML DSIG does not
>> > presently define a URN for either of these algorithms. Therefore, we
>> > request that the XML DSIG group add URNs for these algorithms, e.g.,
>> >
>> > http://www.w3.org/2000/09/xmldsig#md5
>> > http://www.w3.org/2000/09/xmldsig#rsa-md5
>> >
>> > If XML DSIG doesn't define these, we will have to define our own URNs;
>> > however, given the very high likelihood of the use of these two
>> > algorithms, we believe it would be in the best interest of the XML DSIG
>> > user community to have W3C specify these URNs.
>> >
>> > Regards,
>> > Glenn Adams
>> > Chair, ATSC T3/S17 DASE Specialist Group
>> >
>> >
>> >
>>
>>
>>
>>
>>
>

Received on Thursday, 5 April 2001 15:48:58 UTC