CheapHostUK and the Post-Quantum Future

Published 14 October 2026 by Jack Bull

CheapHostUK is making post-quantum readiness a priority for our hosting platform. Over the coming months we will roll out post-quantum protection for the connections to your websites, email and server access, and prepare our platform for the next generation of website certificates, known as Merkle Tree Certificates.

This post explains what post-quantum security is, why it matters now rather than in ten years, and what we are doing about it.

What is post-quantum security?

Every time someone visits your website over HTTPS, their browser and our server agree on a secret key to encrypt the connection. Today that agreement relies on maths problems that normal computers cannot solve in any useful amount of time.

A large enough quantum computer could solve those problems. That machine does not exist yet, but governments and researchers expect one within the next decade or so. The UK National Cyber Security Centre has asked organisations to plan their migration now, with the most important systems moved by 2031 and everything by 2035.

Post-quantum cryptography means encryption methods that a quantum computer cannot break. In 2024 the US standards body NIST published the first official post-quantum standards, including:

  • ML-KEM for agreeing secret keys (encrypting connections)
  • ML-DSA for digital signatures (proving a website is who it says it is)

Why it matters today: "harvest now, decrypt later"

An attacker does not need a quantum computer today to cause a problem later. They can record encrypted traffic now, store it, and decrypt it years from now once the technology exists.

Anything that still needs to be private in five or ten years, such as login details, customer records or business emails, is at risk from this today. That is why protecting the connection itself is the urgent part.

How post-quantum connections work

The method being adopted across the web is called hybrid key exchange, and the most common version has the slightly unfriendly name X25519MLKEM768.

It combines two methods at once:

  1. X25519, the trusted method already used by almost every secure website today
  2. ML-KEM-768, the new post-quantum standard

The browser and server run both and mix the results into a single secret key. To read the traffic, an attacker would need to break both methods. If ML-KEM ever turned out to have a flaw, X25519 would still protect you today, and if a quantum computer breaks X25519, ML-KEM still protects you tomorrow.

The best part is that visitors do not need to do anything. Current versions of Chrome, Edge and Firefox already support hybrid key exchange and use it automatically whenever the website's server supports it. Older browsers simply fall back to the normal method, so nothing breaks.

Merkle Tree Certificates: the next generation of SSL

Encrypting the connection is only half the job. Your visitor's browser also needs proof that it is really talking to your website and not an impostor. That proof is your SSL certificate, and it is protected by a digital signature.

The obvious fix is to swap today's signatures for post-quantum ones like ML-DSA. The problem is size. A post-quantum signature is around 2,420 bytes, compared with 64 bytes for a typical signature today, and a normal connection carries several of them. Replacing them all would push every secure connection past 10 KB of extra data, slowing sites down and causing failures on some networks.

How Merkle Tree Certificates solve this

Instead of signing every certificate one by one, a certificate authority groups thousands of certificates into a batch and arranges them in a structure called a Merkle tree. It then makes one post-quantum signature for the whole batch.

Browsers download those batch signatures in the background, separately from your website. When someone visits your site, the server only needs to send a small proof that your certificate is in a batch the browser already trusts. The result is post-quantum protection with connections that can be even smaller than today.

Merkle Tree Certificates also build in certificate transparency, the public log that helps catch fraudulently issued certificates, as part of how every certificate is issued.

Who is behind it

Google Chrome has said Merkle Tree Certificates are its preferred route to post-quantum certificates on the web. Let's Encrypt, which provides the free SSL certificates on our hosting, announced in June 2026 that it will support them. It plans a test environment in late 2026 and a production service in 2027. Your existing certificates will keep renewing exactly as they do now in the meantime.

What CheapHostUK is doing

Our plan has three stages, starting with the part that protects you most right now.

  1. Upgrade the platform. We are moving our servers to AlmaLinux 10 with OpenSSL 3.5, the first long-term supported release of the core encryption library to include the new post-quantum standards.
  2. Switch on post-quantum connections. Once upgraded, we will enable hybrid X25519MLKEM768 key exchange for:
    • websites (HTTPS)
    • email (secure IMAP, POP3 and SMTP)
    • server access (SSH and the control panel)
  3. Adopt Merkle Tree Certificates. When Let's Encrypt and the web server software support them, we will enable them alongside your normal certificate. Visitors with supporting browsers will get the new certificate and everyone else will still get the current one.

We will keep normal encryption running alongside the new methods throughout, so older devices and browsers continue to work.

What this means for you

You do not need to do anything. There is nothing to install, no settings to change and no extra cost. Your SSL certificates will keep renewing automatically, and the upgrades will happen on our side.

What you get is hosting that protects your visitors' data against today's attackers and tomorrow's quantum computers, and a platform that is ready for the next generation of web certificates as soon as they arrive.

We will post updates as each stage goes live. If you have any questions about post-quantum security or your hosting, get in touch with our support team.

Jack Bull
CheapHostUK