A PKI Rant: the Free (as in free beer) Certificate Problem

Intro

Someone asked me what I had to object to this article about free certificates versus paying ones.

The competing interests problem

First of all, I agree that many CAs (Certificate Authorities) are overselling their certificates, granting them properties or responsibilities that are not factual or even accurate on the technical level. The examples provided in the article are excellent. Where my opinion starts to diverge is near the conclusion. Most people will say that the following is pure FUD, and they would not be absolutely wrong. I have nothing to prove my statements; these are hypotheses, and things to look out for. Truth is I don't feel like I am not FUDing, or I would not speak up. I think I am just being extra precautious.

First, I find amusing that many people like to quote "if that is free, then you are the product", but when it comes to Let's Encrypt, they forget this statement and enjoy their certificates carelessly. So, you might ask: "How am I a product, when I am a client of Let's Encrypt? They are not selling my information, and even if they were, all they have on me and my website are public data". True. Your information is not a good for Let's Encrypt, as far as I know. What you are, however, is a wallet, who is no longer opening to give money to any CAs. You see, operating a CA is not free, nor even cheap (especially when you consider that Let's Encrypt staffing budget was a whooping $2.06M for 10 people in 2017 ). So if you get your certificates for free, someone is paying for them. Let's see, "platinum sponsors" (over $300K annually):

• EFF: OK.
• OVH: they make a heavy usage of Let's Encrypt for their shared hosting; OK.
• Cisco and Akamai: hmm, OK.
• Mozilla and Chrome? Uh-oh.

You see, if Let's Encrypt is giving certificates for free, other CAs won't sell any, because people know that there is no difference between a paying DV certificate and a Let's encrypt DV certificate (or now, they know, thanks to the aforementioned article). Since browsers are increasingly lowering the value of EV certificates, people have less and less incentive to pay for them. (Did you notice there is no longer any green bar (or indicator for that matter) in Chrome?) Thus, people won't buy DV or EV certificates from commercial CAs. What will happen to them? They will either shut down their business or become increasingly less secure, because of the lack of funding. Good riddance will say those that consider they have been swindled enough by these CAs. But what the sponsors of Let's Encrypt are doing, really, is leading a war of attrition on commercial CAs by sponsoring an organization that is losing money with each emitted certificate. That's called unfair competition and that is the road to monopolies, too-big-to-fail entities, and single point of failure. That is also the road to an entity whose main sponsors are consumers of the product, and who may have competing interests.

What do you think will happen if, say, Google requires drastic changes in CA policies at the CA/B Forum and the main CA is also dependent on Google's funding to exist and operate properly?

The Certificate Transparency problem

Also, you may consider that free certificates are a bane because people act more carelessly with what is literally worthless, than if they had paid $1 for it. Did you ever come across people who are registering certificates during their boot-up procedures and throw them away during the shutdown procedure (docker containers, hello!)? Well, these certificates are ephemeral only if you consider the registrant.

You see, Let's Encrypt is not all bad; they have implemented ACME, and they started registering all their certificates to Certificate Transparency (CT) logs long before April 2018, when it became required by some browsers. For those not familiar with CT, it is a collection of append-only logs where certificates emitted by ("public") CAs are registered, for them to be publicly auditable. The important word in the previous sentence is "append-only". That means that the so-called ephemeral certificates are logged forever in these CT logs. This causes massive scaling issues on the CT ecosystem, because log operation requires a lot of memory and the CT logs are literally spammed with free certificates. This, in turn, causes CT log sharding (certificates are logged into different CT logs based on some criteria), which increases the difficulty for website owners to monitor these logs and use them properly.

Conclusion

If DV certificate price was low but non-null, commercial CAs would still be able to exist, and Let's Encrypt would be less dependent on their sponsor and less influenced by their agenda and pressures. So I dare say that free certificates are actively harming the web PKI.