Certificate and CRL Profile and Public Key Algorithms

1
Certificate and CRL ProfileandPublic Key
Algorithms

• Russ Housley Tim Polk
• Dec. 13, 2000

2
Status

• New algorithms draft posted in November
• draft-ietf-pkix-ipki-pkalgs-01.txt
• Ready for WG Last Call now
• New son-of-RFC 2459 posted in November
• draft-ietf-pkix-new-part1-03.txt
• Son-of-RFC 2459 will be ready for WG Last Call in
  Late January 2001

3
Algorithms

• It is done
• However, some people think that it should specify
  a MUST implement certificate and CRL signature
  algorithm

4
Profile Modifications (1 of 2)

• Recommended support for pseudonym to align with
  QC
• Support for inhibit any-policy extension now
  required for conforming clients
• Permit use of subject directory
  attributes extension
• One new IETF extension
• subject information access

5
Profile Modifications (2 of 2)

• Removed public key validity period from the path
  validation algorithm inputs
• Removed the issuer unique identifier from the
  trust anchor information
• Aligned policy mapping processing with
  X.509-2000 rules
• Other minor clarifications

6
Remaining Profile Work

• More minor clarifications
• relying party can supply constraints to the
  validation algorithm via inputs, not initial
  state variables
• CRL DP extension explanation text
• Finish removal of UIDs from path validation
  algorithm (missed one place)
• Name constraints

7
Name Constraints

• The relying party may be interested in using an
  alternative name form, such as the rfc822name
• The CA MUST be able to constrain the contents of
  alternative names without requiring that all
  certificates in the chain include the
  constrained name form

8
 X.509 and Name Constraints

• Semantics of excluded subtrees are clear
• Semantics of permitted subtrees are subject of
  some dispute
• PKIX Folks permitted subtrees are satisfied by a
  certificate if it contains one or more acceptable
  names
• X.509 Folks permitted subtrees are satisfied
  when every subsequent certificate contains the
  specified name form and that name is within the
  subtree

9
Name Constraints Example

• Cert 1 Cert 2
• Issuer cUS,cnCA1 cUS,oXX,cnCA1
• Subject cUS,oXX,cnCA1 cUS,oXX,cnCA2
• Alt Name (none) (none)
• Constraints permit cUS,oXX (none)
• Cert 3
• Issuer cUS,oXX,cnCA2
• Subject (empty)
• Alt Name alice_at_xx.com

10
Way Forward

• Two Alternatives
• Clarify X.509 so it works for PKIX-style paths
• Develop new IETF name constraints extension
• Clearly, the first alternative is preferable
• Not in our control!
• How long should we wait?