Most of the world’s governments tell you that you need to be post-quantum prepared by 2030-2035. For example, the US government says critical infrastructure should be key-exchange-prepared by the end of 2030 and authentication-prepared by the end of 2031 (ignore for now that they have the threats exactly backward). Non-critical infrastructure has until the end of 2035. There are a few governments saying critical infrastructure should be prepared by 2029, and many large tech companies, such as Google, Cloudflare, and Microsoft, say they plan to be prepared by 2029.

But what happens if Q-Day happens in 2028?

I cover this topic in my latest post-quantum books, Becoming Post-Quantum: Your Guide to Post-Quantum Success (https://www.amazon.com/dp/B0HHTBDZ7T) and Becoming Post-Quantum: Your Post-Quantum Project Plan (Companion Book) (https://www.amazon.com/dp/B0HJJJ675G).

This isn’t a rhetorical question. IonQ has recently stated (https://www.ionq.com/news/ionq-publishes-worlds-first-fully-compiled-end-to-end-blueprint-for-breaking-256-bit-elliptic-curve-signatures) that it is realistic that its quantum computers could break traditional asymmetric cryptography used by everyone by 2028.

To be clear, a paper is not a working cryptographically-relevant quantum computer. But it is a clear sign that IonQ thinks that it is not out of the realm of possibility.

I wrote about this last week: https://www.linkedin.com/pulse/should-you-post-quantum-prepared-2028-roger-grimes-vo9le.

Note: It takes a lot more than just stable, logical working qubits to make a cryptographically-relevant quantum computer. Marin Ivezic’s analysis is the best I’ve seen on the subject: https://postquantum.com/crqc-capability-framework/. But getting lots of stable, usable error-corrected qubits is one of the biggest challenges, if not the most challenging part.

Most organizations haven’t even started an official post-quantum project yet. They are late. They need to start now! ASAP!!

But even if your organization has started an official post-quantum project, it’s likely that the estimated “Q-Day” (i.e., the day when the first quantum computer breaks traditional asymmetric encryption) that the entire project is running on is probably 2030-2035.

What happens if Q-Day happens in 2028 or 2029?

Well, you’ve got to accelerate your post-quantum project, of course. All of it. It would be a massive immediate refocusing of resources. It would likely result in your organization being less efficient and productive (unless you are a vendor in the post-quantum space).

You would have to reach out to your immediate boss, executive management, and the board of directors, if you have one, and tell them what just happened. Then you would gather all the necessary resources for an emergency meeting. You would immediately start your cryptographic inventory. Instead of having a year plus to conduct it on all critical systems, you would start conducting it focused first and best on your top critical systems. Ultimately, you would want your cryptographic inventory finished as fast as possible (e.g., a week, a month, a quarter) on your most critical assets.

You would then make emergency decisions regarding what can be reconfigured, what needs to be upgraded, what needs to be replaced, what needs to be decommissioned, and what needs to be physically isolated. You would be making these decisions quickly.

You might need to hire extra resources well beyond what you have today to conduct the post-quantum project superfast. Do you have those post-quantum vendors selected today? Do you know any? If not, start figuring out whom to call when. What cryptographic inventory software will you use? None are perfect. None inventory everything. But you need to use one (or more) to help you collect your cryptographic inventory as quickly as you can. You should do your research and make these two selections now, so you'll have them when you need them. [Hint: You need them now, regardless of Q-Day dates.]

On a practical note, if your adversaries can use quantum computers against you (you’d have to calculate the risk of them actually doing so), you would need to implement monitoring tools, processes, and policies to be able to detect a quantum compromise. Is there a way to detect a successful quantum attack? For key exchange breaks, probably not. Other than you learn that previously protected information seems to be known by unauthorized entities. For authentication breaks, you would look out for fake digital certificates and use, and other related artifacts, such as fraudulent successful logons, fraudulent websites with fraudulent “valid” digital certificates. You would need to threat model the various quantum threats against your environment and then create and implement the appropriate protective and detective controls.

You would need to update your SOC (if you have one) and potentially your incident response policies and procedures. How do you respond to a quantum attack if you actually detect one? How do you respond to stolen data? How do you respond to a fraudulently used “valid” digital certificate and its use? In the latter case, you would certainly get the fraudulently used digital certificate revoked, warn stakeholders of the use, and get other related fraudulent assets removed and/or taken down. Ultimately, you need to threat model the various quantum attacks that would be possible against your company and take the appropriate preventative, detective, and incident response controls, like you would against any threat. Only this threat is quantum and new.

I would also recommend that you focus on mitigating authentication threats first (https://www.linkedin.com/pulse/us-government-gets-pqc-threats-exactly-backward-you-should-grimes-sx7ee) over key exchange threats, if you can’t do them both at the same time. This goes counter to every other post-quantum expert telling you what to do first. I’m right. They are wrong.

Regardless of whether Q-Day comes early or not, it’s cheaper and better to do it sooner than later. I wrote about that here: https://www.linkedin.com/pulse/why-become-post-quantum-now-versus-later-roger-grimes-wiboe.

With this post, I just want you to consider what you and the world are going to look like if Q-Day happens years earlier than most governments are telling you to be prepared for. There is at least one quantum computer vendor that is saying it’s not insane to think it might happen in 2028 or soon thereafter.

The possibility is non-zero. You need to make that part of your post-quantum plans. It would be irresponsible not to.