up:: What’s At Risk
Are my passwords at risk?
Largely no, and this is one of the genuinely reassuring answers in the whole subject.
Passwords sit on the half of cryptography that survives. A quantum computer dents it rather than breaking it, and the dent is handled by things that are already standard practice. The threats to your passwords are the ones they always were: reuse, phishing, and companies storing them badly.
There’s one real caveat, and it’s about your password vault rather than your passwords.
The short version:
- Companies store a scrambled fingerprint of your password rather than the password itself, and that fingerprint can’t be turned back into the original.
- That fingerprinting sits on the surviving half of cryptography, so Shor’s method doesn’t apply to it.
- The quantum tool that does touch it, Grover’s method, roughly halves the effective strength, which longer values already account for.
- Modern password storage is deliberately slow, which multiplies the cost of every guess and blunts the quantum advantage further.
- The real caveat: a password vault copied off a network today could be opened later if the connection protecting it used the broken half.
- The actual threats to your passwords remain reuse, phishing, and bad storage by companies.
Why don’t passwords break the way other things do?
Because of how they’re stored, which surprises most people.
A well-run company doesn’t store your password. It stores a scrambled fingerprint of it, produced by a one-way process. When you log in, it fingerprints what you typed and compares the two. The original is never kept anywhere.
That matters here because the fingerprinting process belongs to the surviving half of cryptography. The quantum method that breaks encryption keys, described at What is encryption?, works against a specific mathematical structure that password fingerprinting doesn’t have.
So the headline attack simply doesn’t reach them.
What about Grover’s method?
That’s the honest caveat, and it’s modest.
There’s a second quantum technique that speeds up brute-force guessing. Rather than breaking anything outright, it makes searching faster, roughly equivalent to halving the strength of what you’re searching for.
Two things blunt it in practice.
Modern password storage is deliberately slow. Systems like bcrypt, Argon2id, PBKDF2, and scrypt are designed to be expensive to compute, and some are designed to consume large amounts of memory as well. That cost multiplies against every single guess, and it applies to a quantum attacker exactly as it applies to a conventional one.
Halving strength is a known quantity. Security people have planned around this for years, and it’s handled by using longer values, which has been standard advice for a long time anyway.
Full technical treatment at Passwords in a Quantum World.
So what about my password manager?
This is the part worth paying attention to, and it’s a different question from the one above.
Your vault is protected by your master password, which is fine. But the vault itself travels: it syncs between your devices, backs up to a server, and crosses networks. If a copy of your encrypted vault was taken while it was in transit, and the connection protecting it used the half of cryptography that breaks, then that copy could be opened later.
What would be inside is every account you had at the moment it was captured.
The practical response is ordinary: use a long, unique master password, turn on two-factor authentication, keep the application updated so it gets the new protections, and change passwords for anything genuinely important periodically, which shortens how long any captured snapshot stays accurate.
What actually threatens my passwords?
The same things as always, and they’re far more likely to affect you than anything quantum.
| Real threat | Why it matters |
|---|---|
| Reusing passwords | One breached site becomes access to everything else. This is exactly how 14,000 23andMe accounts were entered, exposing 6.9 million people. |
| Phishing | Someone convinces you to type it in. No cryptography helps. |
| Companies storing passwords badly | Plain text or weak fingerprinting, discovered only after a breach. |
| No two-factor authentication | A stolen password becomes an account without it. |
| Malware on your device | Captures what you type, before any encryption is involved. |
Every one of those is more urgent for you personally than the quantum question, and the fixes are the well-known ones.
Questions people ask
Do I need to change all my passwords? No, and there’s no quantum reason to. Change reused ones, because that’s a real and current problem.
Should I make my passwords longer? Longer is better and always has been. A password manager generating long random values handles this without you thinking about it.
Is two-factor authentication affected? Codes from an app are unaffected. Hardware security keys use the half of cryptography that breaks, and manufacturers are working on that, though a stolen or copied authentication exchange is far less useful to an attacker than stored data is.
What about the passwords already saved in my browser? Same as a password manager, with the caveat that browser storage is generally less protected. Keeping the browser updated matters.
So this is one thing I can stop worrying about? For passwords themselves, broadly yes. Put the worry into your vault syncing, and into reuse, which is the thing most likely to hurt you.
Where to go next
- What of mine is actually worth stealing? covers what does matter.
- What about my Bitcoin? covers the wallet question, which is genuinely different.
- What should I actually do? is the full personal list.
Go deeper into the technical detail
The technical version is Passwords in a Quantum World and Grover’s Algorithm.
These open the Post-Quantum Field Guide, a separate site written for security professionals.
Last verified 2026-07-30 · Maintained by Addie LaMarr, LaMarr Labs.