Re: [Danish] Charter Text and the Problem Statement

[Hannes Tschofenig <[e-mail]>]

Thanks for your feedback, Ash.

It is interesting that you mention the network access authentication use case. Do you envision EAP-TLS in combination with Danish to work architecturally differently than the current EAP-TLS-based approach?

You write:
“Credential issuance very often requires the device and the person bootstrapping the identity to be in the same place”

Binding the user to his or her device typically takes some time. It often requires the user to log into some service and to “add” the new device often by demonstrating physical possession. Of course, this is the way how it works for end consumer products, where scalability is less of an issue because you are probably not going to buy thousands of smart coffee machines. For a commercial setup, the process often works different but it very much depends on the type of industry vertical you are in. There is often a non-irrelevant configuration step involved as well. For example, with commercial indoor lighting professionals need to configure different lighting themes.

I don’t see any of this user-related interaction being covered as part of the chartered work.

Ciao
Hannes

From: Ash Wilson <[e-mail]>
Sent: Wednesday, June 16, 2021 11:28 PM
To: Hannes Tschofenig <[e-mail]>
Cc: [e-mail]
Subject: Re: [Danish] Charter Text and the Problem Statement

Hi Hannes,
Thanks for the questions, and apologies for keeping you waiting on answers/clarification.

On Wed, Jun 16, 2021 at 4:12 AM Hannes Tschofenig <[e-mail]<mailto:[e-mail]>> wrote:
Hi all,

I have been reading through the charter text in an attempt to understand the problem statement.

Two problems are mentioned:


1)  Challenges with naming collisions in the IoT space.



2)  Credential issuance is time consuming.


Ad 1: Reading through the text it feels like naming collisions are a big thing in IoT. I have not heard about those problems. Could you elaborate?
Certainly. I'll use a hospital as an example environment.

Within a hospital, it is desirable to implement 802.1x authentication using EAP-TLS for access to protected networks. EAP-TLS enables the use of PKI-based identity to authenticate an entity for network access.

When implementing EAP-TLS for network access, RADIUS is a common protocol/server used for authentication behind the switch or wireless access point. Guidance for configuring RADIUS recommends the use of only one CA certificate for authenticating supplicant certificates. This guidance can be found in the wild in Freeradius configuration files for EAP-TLS, related to the 'ca_file' configuration directive.

CAs guarantee the uniqueness of an entity's name within the scope of the CA, but have no method for enforcing name uniqueness across other CAs. For instance, CA1 and CA2 may both sign certificates for entities with the same name. If CA1 and CA2 are both trusted by the RADIUS server, and two entities named "medicaldevice123" exist, one per CA, then the resulting ambiguity makes it difficult to appropriately apply access controls. This ambiguity is mitigated by operating a single organizational PKI, and requiring identities issued by that single organizational PKI for EAP-TLS authentication.

Onboarding devices to organizational PKI requires time and effort. Oftentimes some sort of skilled labor and/or dedicated infrastructure for automating the onboarding process is involved. DANE allows us to bind a DNS name to a public key, and mitigates the ambiguities introduced by the use of multiple CAs. An organization can only issue working identities within its own namespace in DNS. Since naming ambiguity can be mitigated using DANE, we may now choose to use manufacturer-issued PKI, represented in DNS, for authenticating entities.

From the hospital's standpoint, the IT staff no longer needs to manage the process of onboarding devices to organizational PKI. The device arrives on-site with an identity which can be immediately used for network authentication.

You add that “In response to the challenges related to

ambiguity between identities issued by different CAs, application owners

frequently choose to onboard IoT devices to a single CA.”. Is that a good or a bad development?
It is a good development if the organization really wants to directly manage all of the credentials for all of the application participants. The effort and rationale behind BRSKI (RFC 8995) suggests a desire to make onboarding to organizational PKI easier to automate.

If a supplier issues a trustworthy identity for a device, and DNS prevents another PKI from issuing working credentials under the same name, then issuing another identity via organizational PKI becomes superfluous. This is where we think that time and effort can be saved, because the skills required for onboarding do not need to include the management and issuance of identities under organizational PKI.

Ad 2: Is it really true that credential issuance is time consuming? Why is that? For whom is it time consuming?
Credential issuance very often requires the device and the person bootstrapping the identity to be in the same place. Some platforms and protocols exist to make that process easier (like BRSKI) or less human-involving. The time investment seems to be on the part of both the manufacturer (in issuing the IDevID) as well as the organizational IT staff, who manage the organizational PKI.

Ciao
Hannes

PS: You use the term “Certificate Authority (CA)”. It is actually called “Certification Authority”.


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