Liaison to IETF on the resolution of DR320
|From Contact||Xiaoya Yang|
|Response Contact||Xiaoya YANG
|Deadline||2008-03-01 Action Taken|
At our recent ITU-T SG17 meeting in Geneva we discussed and rejected Defect Report 320 (http://www.x500standard.com/uploads/Defects/DR_320.pdf) from AFNOR. This DR advanced an argument that Distinguished Names may not be unique and as such, the DN of the Certificate User may not be unique. The directory group believes that Distinguished Name values must be unique and unambiguously identify a single entity, hence the use of the term Distinguished. The DR states â€œthe DN of the issuer name cannot be guaranteed to be uniqueâ€?. X.509 takes its definition of DN from X.501. Clause 9.2 of X.501 specifies the definition of DistinguishedName. This clause states A name shall be unambiguous, that is, denotes just one object. Clause 9 goes on to state: It is the responsibility of the relevant naming authority for an entry to ensure that this is so by appropriately assigning distinguished attribute values. Allocation of RDNs is considered an administrative undertaking that may or may not require some negotiation between involved organizations or administrations. This Directory Specification does not provide such a negotiation mechanism, and makes no assumption as to how it is performed. The standard takes an axiomatic view of the concept that a distinguished name unambiguously identifies a single entity. Things break if two entities identify themselves using the same name. We don't let two entities have the same domain name or the same email address. Why? - because things wouldn't work. The directory group does not accept the DRâ€™s basic argument. We believe that if two entities present the same name and a CA issues a certificate to each, that CA made a mistake - not a naming authority mistake, since a CA is not an naming authority (although one entity can be both), but an entity to key binding mistake that leads to confusion and even worse, a security risk. We believe that if two entities claim the same name as top level CAs, there is a political/procedural breakdown much like the domain ownership arguments we have seen. No one argues that the Internet protocols should be modified to solve that problem. The conflict is resolved and one entity is assigned the name. The group believes that this is the only reasonable solution for Distinguished Naming. One votes for the CA of choice by configuring it as an anchor. One of the participants in the directory meeting stated that Certification Authorities are being deployed with names not acquired from naming authorities but with names arbitrarily chosen assuming that no other CA is or will be operating under that name. That participant further stated that the IETF provides no guidelines on ensuring that the names of CAs are unambiguous. The directory group requests the IETF PKIX group to comment on this statement. If the statement is correct, we ask the IETF to consider putting a mechanism in place to prevent conflict, e.g. a list of existing CA names that deployers of new CAs could check for naming conflicts.