Comment by LoganDark
1 day ago
This post completely fails to address one of my biggest fears with a batched approach: waiting for a brand new certificate to be provisioned for a server that does not already have one. If batches are executed too frequently, then clients will have too big a database to maintain. If batches are executed too infrequently, then I have to wait a while to get my first certificate. Are they doing anything about this or is this just how it'll be with these new quantum-resistant certificates?
Great question! Of course, we'll continue to provide more information as we firm up more details. This is an area that's not locked down yet, but I can give a sneak preview of what it might look like.
We expect batches to be produced quickly, on the same order of magnitude as current CT logs - somewhere in the 0.5s to 5 second range. This is an existing problem since (at least some) CT logs do the same batched behaviour.
Now, there is a catch with MTCA: That gets you a "standalone" certificate, which works just like a certificate does today. But it's big, still. To get the new, small certificates (landmark-relative), you will have to wait for the next landmark. Based on current planning and discussions with Chrome, we expect that to be hourly for short-lived certs, and 4 hours for longer-lived certificates.
So you'll get a big cert instantly, but you might have to wait an hour or 4 to get a certificate. So your new website can be online quickly, but with some downsides until you get the small landmark-relative cert.
(I work at Let's Encrypt)
You'll be able to immediately use use a "standalone certificate" while waiting for the batch to be created. The tradeoff is that the standalone certificate will have multiple huge ML-DSA signatures.
They can't address it because nobody knows the answer yet. That's why their plans https://letsencrypt.org/2026/06/03/pq-certs#our-plans are to work with experts to solve the engineering challenges in the coming years, rather than announce a gift-wrapped solution today.
If this fear of yours is particularly poignant, I invite you to share it with the forum so they have it in writing. It makes it easier for them to consider it as they work on a solution.