Is OpenID Connect suitable for Internet of Things?

Question

I am studying Authentication and Authorization protocols for my master thesis and I found that probably the best 2 alternatives are OpenID Connect and SAML 2.0 (actually, an European, SAML-based project in which my company was involved 4 years ago called SENSEI).

The purpose of the thesis is the extension of an existing Internet of Things system, which is basically a catalog of streams with information fetched from millions of sensors, and provide AAA (including Accounting), transforming it into an actual Marketplace of streams where people might pay to be subscribed to some streams.

So far, I think OpenID Connect will be a better choice over Sensei and SAML. Reasons are the huge amount of information, documentation, libraries and the companies which support this standard. Also is more developer-friendly and recent. However, I read the following paragraph written by OWASP in this article

While OpenId has taken most of the consumer market, SAML is often the choice for enterprise applications. The reason for this is often that there are few OpenId identity providers which are considered of enterprise class (meaning that the way they validate the user identity doesn't have high standards required for enterprise identity). It is more common to see SAML being used inside of intranet websites, sometimes even using a server from the intranet as the identity provider.

So I was wondering if you, please, could help me with the following questions:

1. Do you think also that SAML is maybe more suitable for enterprise projects like mine? Is it true that OpenID is more user-oriented?
2. I have to think also about the Trust model regarding the sensors in order to be sure that they are reliable sources of information. Therefore, do you think it is a good idea to use the same protocol for: 1) the users who want to be logged in the system and 2) the devices which should prove they are trusted sources with non-faked data?
3. Related to the previous issue, if I could use OpenID Connect for devices, how could I make them to be authenticated without an email or password? I was thinking in the UUID as identifier but I was told it is not a good idea and also read the same on this StackOverflow thread.
4. Does anyone know if there exists any well-known protocol to handle or support Accounting in a system? As far as I know OpenID Connect supports Session Management but not Accounting at 100%.

Thanks in advance.

Answer 1

I'm not sure I can answer all your questions here... But I'll give it my best shot, based on my experience and knowledge. And, I'll say that you're being somewhat nebulous with the question (maybe you need to, so as not to expose you billion dollar idea). As such, my answer is really (admittedly) more likely to be considered a discussion point, maybe, than an "answer".

OIDC (OpenID Connect) is new, as is the IoT (Internet of Things). Enterprises are rarely bleeding edge, unless they are dragged into it kicking and screaming by a bigger enterprise partner. That being said, OIDC is built on top of OAuth2.0, so it has understanding out there, and enterprises are really in the take-up phase (IMO), and many of the purchased platforms (like my company's) support it at [current draft-1].

What I think is important to point out is that neither SAML or OIDC is "authentication". It's a standards-based method by which you can carry attributes from an authentication point to an application point that needs to KNOW who or what is connecting to it. Your users could connect one way, your "sensors" another. Or maybe both. Or maybe the opposite. If you're building the next trillion dollar social media site, do you want to limit the ways that your users can join up?

In reference to your question about OIDC and Sensors... I would suggest a certificate-based authentication system, if these things are truly just sitting out there on their own. Again, however, OIDC (and SAML) isn't an authentication system, really. It doesn't do the "front line" of the authentication - it provides a method by which an identity can be carried to the relying party based on a validated claim with a trusted partner. UUID may well be a good choice for the "username" of the device, but it certainly shouldn't be the "password".

Finally, I'm not quite sure what you're asking for with accounting. Are you wanting to charge a user for access to your IoT device streams with, say, microtransactions (interesting concept, if so). Again, neither SAML nor OIDC provide for something like this, at least as far as I am aware of. Accounting (and billing) would have to be built into the application.

HTH -- Andy