Acme, a brief history of one of the protocols which has changed the Internet

(I do work at Mozilla now, but this predates me. Still think it's one of its most significant (and sadly often overlooked) contributions though.)

LE allowed more sites to get certificates. This has obvious benefits for e-commerce, for example

But so-called "tech" companies, e.g., "Big Tech", have, since before and after LE was started, continued to perform the largest mass scale intentional erosion of privacy in human history

The exfiltrated data is encrypted in transit using TLS. This may prevent ISPs or other passive network observers from competing with the so-called "tech" companies in the data collection, surveillance and ad services business

Arguably the use of TLS certificates increases privacy from ISPs or other passive network observers, but it does not increase privacy from so-called "tech" companies, who are perhaps the greatest threat to privacy that computer users face. Their "business model" depends on violating privacy norms

And, in fact, commercial CA certificates as pre-installed in browsers and required on the www ("WebPKI") effectively obstructs computer users from monitoring their own egress traffic in real-time. Hence corporations and other computer users must work around "WebPKI" to perform "TLS inspection"

M

I read NYT with no cookies, no Javascript and no images. Only the Host, User Agent (googlebot) and Connection headers are sent. TLS forward proxy sends requests over internet, not browser. No SNI. No meaningful "fingerprint" for advertising

This only requires accessing a single IP address used by NYT. No "vendors"

TLS is monitored on the network I own. By me

I inspect all TLS traffic. Otherwise connection fails

I’d be very surprised if they haven’t had several of the root trust entities compromised from day one. I wouldn’t rely on TLS with any of the typical widely-deployed trust chains for any secrecy at all if your opponent is US intelligence.

Otherwise I find it a scourge, particularly when I want to run https over a private network, but browsers have a shitfit because I didn't publicly announce my internal hosts.

There's plenty of traffic that has no need to be encrypted, and where not much privacy is added since the DNS queries are already leaked (as well as what the site operator and their many "partners" can gather).

I'm glad you can get free certs from Let's Encrypt, but I hate that https has become mandatory.

(Seriously: I strongly suspect that Let's Encrypt's ISRG are the good guys. But a security mindset should make you question everything, and recognize when you're taking something on faith, or taking a risk, so that it's a conscious decision, and you can re-evaluate it when priorities change.)

The actual communication is secured by a public/private keypair which is separate from the CA certificate.

Browsers have a set of certificates "pre-accepted", these are the default root certificates. There have been issues with some of them over time (e.g. DigiNotar) and they hav changed over time. If you hear of someone speaking about the "CA cartel" this is what they mean.

So a compromised CA can make you think you are talking to someone, like your bank, when you are not. But it doesn't enable snooping on traffic on the wire.

A CA can protect from this compromise by keeping the root private key entirely offline and signing a couple intermediate CA certificates. Then, if one of those intermediate CAs gets compromised, it can be revoked and a new intermediate CA created. You as a user of the CA can't do much though-either you choose to trust it (or delegate that trust) or don't.

You can create your own self-signed root CA certificates and client/server certificates signed by that CA fairly easily. But you then have to add the root CA as a trusted certificate into every device you want to use it, including those of your friends, employees, etc. This isn't quite as bad as it sounds, the last time I checked even phones would install a new root CA certificate if you opened a .crt file, and deploying CA certificates via Microsoft Group Policy is a thing.

See, SCEP assumes that Bob trusts Alice to make certificates. Alice uses the SCEP server provided by Bob, but she can make any certificate that Bob allows. If she wants to make a certificate claiming she's the US Department of Education, or Hacker News, or Tesco supermarkets, she can do that. For your private Intranet that's probably fine, Alice is head of Cyber Security, she issues certificate according to local rules, OK.

But for the public web we have rules about who we should issue certificates to, and these ultimately boil down to we want to issue certificates only to the people who actually control the name they're getting a certificate for. Historically this had once been extremely hard core (in the mid-1990s when SSL was new) but a race to the bottom ensued and it had become basically "Do you have working email for that domain?" and sometimes not even that.

So in parallel with Let's Encrypt, work happened to drag all the trusted certificate issuers to new rules called the "Ten Blessed Methods" which listed (initially ten) ways you could be sure that this subscriber is allowed a certificate for news.ycombinator.com and so if you want to do so you're allowed to issue that certificate.

Several ACME kinds of Proof of Control are actually directly reflected in the Ten Blessed Methods, and gradually the manual options have been deprecated and more stuff moves to ACME.

e.g. "3.2.2.4.19 Agreed‑Upon Change to Website ‑ ACME" is a specific method which is how your cheesiest "Let's Encrypt in a box" type software tends to work, where we prove we control www.some.example by literally just changing a page on www.some.example in a specific way when requested and that's part of the ACME specification so it can be done automatically without a human in the loop.

If a cert has to be renewed once every 3 years, plenty of companies will build an extremely complicated bureaucratic dance around the process.

In the past this has resulted in CAs saying "something went wrong, and we should revoke, but Bank X is in a Holiday Freeze and won't be able to rotate any time in the next two months, and they are Critical Infrastructure!". Similarly, companies have ended up trying to sue their CA to block an inconvenient revocation.

Most of those have luckily been due to small administrative errors, but it has painfully shown that the industry is institutionally incapable of setting up proper renewal processes.

The solution is automated renewal as you can't make that too complicated, and by shortening the cert validity they are trying to make manual renewal too painful to keep around. After all, you can't set up a two-months-long process if you need to renew every 30 days!

- [0] https://letsencrypt.org/2025/12/02/from-90-to-45

Tl;dr is to limit damage from leaked certs and to encourage automation.

There's a TLSA resource record for certificates instead of a TXT encoding.

As far as I know no major browser supports it, and adoption is hindered by DNSSEC adoption.

(There's dozens of us!)

Scroll down to the footer--> click on "Homepage"

Then you will get to his homepage: https://www.brocas.org/