Google moved up its estimated deadline for quantum preparedness in cryptography to 2029—only 33 months from now. That’s earlier than previous deadlines, and they proposed the new post-quantum migration deadline because of two new papers that comprise a big jump in the state of the technology. It’s ahead of schedule, but not altogether unexpected. Cryptographers and engineers have been working on this for years, and as the deadline gets closer, it’s not surprising to see more precise timeline estimates come up.

The preparation for the Y2K bug is not a perfect analogy. Like Y2K, if systems are not updated in time, anyone with a powerful enough quantum computer will be able to more easily insert malware into the core systems of a computer and fake authentication to allow impersonation merely by observing network traffic. These are the threats whose mitigation timelines have been moved up.

But unlike Y2K, there’s a second sort of attack that we already need to be prepared for: quantum computers will be able to decrypt years of captured messages sent over encrypted messaging platforms shared any time before those platforms updated to quantum-proof encryption. That type of attack has been the main focus of engineering efforts so far and mitigation is well on its way, since anything before the upgrade might eventually be compromised.

Fortunately, not all cryptography is broken by quantum computers. Notably, symmetric encryption is quantum resistant. That means that if you have disk encryption turned on, you shouldn’t have to worry about quantum computers breaking into your phone, as long as your system’s keys are long enough. The problem is how you get the keys to do that encryption, and how you authenticate software on your device and in the cloud.

Engineers: Time to Lock In

For those whose work touches on any sort of cryptographic deployment, you’re hopefully already working on the post-quantum transition. If not, you really should be; there are quite a few relevant posts and updates with more information about what this news means for you. Your key agreement systems should be upgraded soon if they’re not already because of store-now-decrypt-later attacks. Now it’s time to prepare for authentication attacks on forged signatures as well.

In some cases, you may need to wait on others to finish their work first. If you’re using NGINX to host websites on Ubuntu, for example, the security settings you need to upgrade key agreement were just released in version 26.04. Updates are rolling out, so keep checking in and upgrade your systems as soon as you’re able to.

Users: Stay Updated, Check on Your Chats

But if you’re not in any position to be updating software or hardware, there may be some additional steps you can take to make sure you're as protected as possible. You’ll want to get the latest post-quantum protections as soon as they're available, so if you don't already have a habit of applying software updates in a timely manner, now’s a good time to start.

If you want to know if the website you’re using or the encrypted messaging app you’re chatting over will leak its data in a few years to anyone storing traffic now, you can search for its name with the word "quantum." The engineers are usually pretty proud of their work and have announced their post-quantum support (like what we’ve seen from Signal and iMessage). If you can’t find that information, you may want to have extra consideration for what you say over the internet, or switch the tools you're using. Those are the big areas to worry about now, before quantum computers are actually here, because they could result in the mass leakage of old messages.

The new deadline means that some technologies are simply not going to make it in time and will have to be left by the wayside, like trusted execution environments (TEEs), due to the slower speed of hardware deployments. TEEs are how companies do private processing on user data in the cloud, and they’re particularly relevant to AI offerings. 

Even now, though they offer more protection than processing data in the clear, TEEs are not as secure as homomorphic encryption or doing the processing on device. Post-quantum, the security level gets much closer to computation on cleartext, and even with strong user controls, that makes it way too easy to accidentally backdoor your own encrypted chats. If you’re worried about the contents of messages in an encrypted chat being exposed, you’ll probably want to completely avoid using AI features that might leak that content, such as summarization of recent chat history and notifications, and reply composition assistance. 

How’s the Transition Going So Far?

The work to update the world to post-quantum is well on its way. NIST finalized the standards for post-quantum cryptographic algorithms back in 2024. The larger platforms, websites, and hosting providers have already updated their algorithms, so even now, you’re probably already using post-quantum algorithms to access some of the internet. Measurements vary pretty widely, but up to about 4 in 10 websites currently support a post-quantum key exchange.

There’s still some work to be done in figuring out how to make the needed changes—for example, the way you find out a website’s private key to make HTTPS possible is being reworked to make room for larger signatures. Some technologies are just coming to market, like the post-quantum root of trust available now in some Chromebooks. In practice, this means that as you think about replacing your current devices in the next few years, you may want to check if you’re picking up hardware that has post-quantum support, if those specific protections are required for your threat model.

For the areas that still need updating, how much can we expect to actually get ready by the new deadline? It’s likely that not every cryptographically-capable device and deployment will be ready in time, and hardware with hard-coded certificates will probably be the last to update. We saw that happen when SHA-1 was deprecated; Point of Sale systems in particular were late adopters. While governments and large companies with quantum computers may not be interested in stealing money from cash registers, they will be interested in accessing secrets about people’s private lives. That’s why it’s so important that everyone does their part to upgrade, to protect the details of private communications and browsing. 

And there’s a good chance that older devices that won’t receive quantum-resistant updates were probably vulnerable to some other attack already. Quantum computation is just one type of attack on cryptography that’s notable for the scale of migration required, and how every public-key cryptosystem and authentication scheme has to do the work to prepare. That’s not a difference in kind, it’s a difference in scale, and some systems will inevitably be left behind.

Quantum preparedness hits different industries and services in different ways, but services that handle communications and financial information are particularly susceptible to risk, and need to act quickly to protect the privacy and security of billions of people.