Subject: [KEYPROV] RE: Where and how to define the undefined URIs for the algorithmes listed in the current PSKC?

From: "Pei, Mingliang" <[email-masked]>
Date: Wed, 17 Oct 2007 22:26:02 -0700

Note that PBE URIs may use the PKCS URI and Key Wrapper URIs in xmlenc
spec. PSKC schema introduces a type for PBE related algorithms as
follows. The question is whether it is necessary to combine them.
 
  <complexType name="PBEEncryptionParamType">
    <sequence>
      <element name="PBESalt" type="base64Binary"
               minOccurs="0"/>
      <element name="PBEIterationCount" type="int"
               minOccurs="0"/>
    </sequence>
    <attribute name="encAlgorithm" type="anyURI"/>
  </complexType>
 
  <complexType name="EncryptionMethodType">
    <sequence>
      <element name="EncKeyLabel" minOccurs="0"/>
      <choice>
        <sequence>
          <element name="KeyInfo"
                   type="ds:KeyInfoType" minOccurs="0"/>
          <element name="OAEPParams"
                   type="base64Binary" minOccurs="0"/>
        </sequence>
        <sequence>
          <element name="PBEEncryptionParam"
                   type="pskc:PBEEncryptionParamType" minOccurs="0"/>
          <element name="IV" type="base64Binary" minOccurs="0"/>
        </sequence>
        <any namespace="##other" processContents="strict"/>
      </choice>
    </sequence>
    <attribute name="algorithm"
               type="anyURI" use="required"/>
  </complexType>
 
Example:
 
      <EncryptionMethod
 
algorithm="http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbes2"
        xmlns="urn:ietf:params:xml:ns:keyprov:container">
          <PBEEncryptionParam
 
encAlgorithm="http://www.w3.org/2001/04/xmlenc#kw-aes128-cbc">
            <PBESalt>y6TzckeLRQw=</PBESalt>
            <PBEIterationCount>1024</PBEIterationCount>
          </PBEEncryptionParam>
          <IV>c2FtcGxlaXY=</IV>
        </EncryptionMethod>
 
which is currently proposed.
 
- Ming

________________________________

	From: Pei, Mingliang 
	Sent: Wednesday, October 17, 2007 10:15 PM
	To: Philip Hoyer; [email-masked]; Hallam-Baker,
Phillip; [email-masked]; [email-masked]; Doherty,
Andrea; [email-masked]
	Subject: Where and how to define the undefined URIs for the
algorithmes listed in the current PSKC?

	All,
	 
	In our effort to use URIs instead of enumerations in PSKC for
EncryptionAlgorithms, DigestAlgorithms, and KeyAlgorithms, we found that
some algorithms don't have a defined / registered URIs yet, mostly, for
the PBE methods and Key Algorithms. Attached please find current laundry
list of the algorithms for their respective URIs, and those that need
some URIs to be defined. We found most URIs defined by XML signature and
encryption specification (xmldsig, additional xmldsig URIs, and xmlenc
).
	 
	Please let us know if you find some places that have defined
URIs for the listed missing ones, or any suggestions where we should
define the new ones, for example, OTP algorithms by HOTP, variours
vendors (VASCO, SecurID (if need one other than current RSA URL)).
	 
	Please see the attached doc for questions. Here are quoted
questions:

	a) Where can we find URIs defined for PBE algorithms?

	PBEs are defined in PKCS#5. The XML version defined the
following URI. One PBE algorithm would need two URIs to define, for
example, PBE-AES128-CBC would be identified with the following two:

	http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbes2

	http://www.w3.org/2001/04/xmlenc#kw-aes128-cbc

	and possibly a third one that identifies key derivative
function.

	b) Shall we define one URI for each PBE method with encryption
such as PBE-AES128-CBC?

	Thank you,
	 
	- Ming

________________________________

		From: Philip Hoyer
[mailto:[email-masked]] 
		Sent: Tuesday, October 16, 2007 9:23 AM
		To: [email-masked]; Hallam-Baker, Phillip;
Pei, Mingliang; [email-masked]; [email-masked]
		Cc: [email-masked]
		Subject: IETF Keyprov PSKC meeting minutes 15/10.07

		Attendees: 

		Philip Hoyer, Ming Pei, Shuh Chang, Salah Macchani,
Phillip Hallam-Baker, Hannes Tschofenig

		1)       Initially decided to tackle the issue of
algorithms that are represented as enumerations in PSKC and if we should
go to a URI based approach that allows for easier extension. There are 3
type of algorithm definitions in PSKC

		a.       EncryptionAlgorithm of the key material in the
container

		b.       DigestAlgorithm to create a digest of the
uncencrypted keys

		c.       OTP Algorithm, identifier of the algorithm that
the key is being used with

		2)       Agreed to change EncryptionAlgorithm and
DigestAlgorithm to change to URI

		3)       Ming Pei to change schema and add minimum list
of URIs 

		a.       Issue, what about PBE related algorithms, no
URIs found by Ming

		b.       Ming Pei to send Phillip Hallam Baker and to
mailing list the list of algorithms for which he has not found URIs.
Philip Hallam Baker will then try to find URIs or get back to authors
with way to proceed

		4)       Discussion about digest of the key for RSA
encrypted keys - Ming, Shuh to check if it is a bad idea - Philip to ask
to the list

		a.       The problem here is that the Digest used for
symmetric algorithms is a keyed digest eg HMAC-SHA1 which is still not
broken. If for transmission of keys wrapped by a public Key of the
receiving party we use a simple digest iof the unencrypted key material,
it might open the container for brute force attacks. Since a keyvalue to
hash value mapping might be much quicker to find than brute forcing
HMAC-SHA1

		5)       URIs for KeyAlgorithm? 

		a.       Fundamentally the people agreed that it is a
better idea but even more than encryption and digest algorithms, OTP
algotihms do not have a defined URI

		b.       Ming Pei to send Phillip Hallam Baker and to
mailing list the list of algorithms for which he has not found URIs
Philip Hallam Baker will then try to find URIs or get back to authors
with way to proceed

		6)       Philip Hoyer proposed to introduce a keyType at
container level with attributes such as algorithm and logo and usage
type that the key can reference (this would avoid repeating all the data
for similar keys within the container) - Everyone agreed that this was a
good idea but  deemed a priority 2 item

		7)       Hannes to investigate what best practice is
regarding URN versioning, current proposal is to add numeric version so
all ietf:keyprov URN should add ':1'

		8)       Should we reorganise PBE to support PKCS5 XML
schema, currently this was deemed to complicate the schema too much so
it was deferred for now 

		9)       Discussion around attributes and elements,
should the ASN.1 document contain the description of the attributes.
Decision for ASN.1document to incorporate attribute definition of PSKC
spec. Hannes to send email to the list.

		10)   Discussion if we need to have a face to face
meeting to align spec. Hannes asked if a set of conference calls with a
precise short agenda. Would be good. Should we have a weekly conference
call? Agreed to have a weekly call on Monday 3pm Central 4pm EDT 9 pm
for 30 minutes

		11)   IV should be moved back to EncryptionMethod since
it is used for symmetric algorithms and not only for PBE (Ming in his
latest revision had moved it to the PBEParams element)

		12)   Discussed initial PIN transmission, Philip invited
for participants to review and agree. If no disagreements Philip Hoyer
will include in October revision of the spec

		 

		________________________________

		Philip Hoyer 

		Senior Architect - Office of CTO

		ActivIdentity (UK)

		109 Borough High Street

		London SE1 1NL

		Telephone: +44 (0) 20 7744 6248

		Direct: +44 (0) 20 7744 6455

		Fax: +44 (0) 20 7744 6249

		Private and confidential: This message and any
attachments may contain

		privileged / confidential information. If you are not an
intended recipient,

		you must not copy, distribute, discuss or take any
action in reliance on it.

		If you have received this communication in error, please
notify the sender

		and delete this message immediately.

_______________________________________________
KEYPROV mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/keyprov