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Post-Quantum Cryptography, Explained Simply

By the BMIC Research Desk · Updated 2026-08-29 · Part of the BMIC Wallet Guide series
Quick answer: Post-quantum cryptography replaces the math problems behind today's wallet security -- which have a known theoretical shortcut on a powerful enough quantum computer -- with different math problems that, based on current research, do not.

Almost every crypto wallet today protects your private key using elliptic-curve cryptography. It is a very hard math problem for any ordinary computer to reverse. It is not, in theory, hard for a sufficiently powerful quantum computer, because of a known method called Shor's algorithm, published in 1994, decades before a machine capable of running it at the needed scale existed.

Post-quantum cryptography is the field built to answer that specific gap. It does not try to make quantum computers less capable -- it changes which math problem your keys depend on, choosing ones that current quantum algorithms, including Shor's, have no known way to shortcut.

The U.S. National Institute of Standards and Technology (NIST) ran a public, multi-year competition among cryptographers worldwide to select which of these new problems were trustworthy enough to standardize. CRYSTALS-Kyber, standardized under the name ML-KEM, was one of the winners, finalized in 2024.

BMIC uses ML-KEM for key protection. That is the entire practical claim: a NIST-vetted algorithm, publicly attacked and reviewed for years by the wider cryptographic community, replacing a scheme with a known theoretical weakness -- not a proprietary or unreviewed method invented in-house.

Nothing here means today's wallets are unsafe right now; no quantum computer capable of running Shor's algorithm against real-world key sizes exists yet. The reason to act ahead of that date is covered separately -- see harvest-now-decrypt-later below.

FAQ

What is Shor's algorithm, in one sentence?

A mathematical method, published in 1994, that describes how a sufficiently powerful quantum computer could solve the specific math problems behind most of today's wallet cryptography much faster than any ordinary computer.

Is post-quantum cryptography the same as quantum computing?

No. Post-quantum cryptography runs on ordinary computers today -- it is simply built on different math problems chosen to resist quantum attacks, not on quantum hardware itself.

What does NIST standardization actually prove?

It shows the algorithm survived years of public attempts by cryptographers to break it, as part of a formal selection process -- not a private company's own claim about its own math.

Does this mean current wallets are already unsafe?

No known quantum computer today can break current wallet cryptography. The concern is about data exposed today being decrypted later -- see the harvest-now-decrypt-later page.

This page is part of The Complete BMIC Wallet Guide, a 20-episode video " series on how the wallet works, why it works, and how it is designed -- including an honest look at what " it does not protect against. See the full series →
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This page is technical/educational information about wallet security and post-quantum " cryptography, not financial advice. No cryptographic system, BMIC included, can promise protection " against every possible future attack.