In cryptocurrency, language matters. Words shape how we think about security, privacy, and risk. Currently, we casually call certain keys in cryptocurrency wallets "public keys". At face value, this makes sense—these keys were intended to be shared openly to prove ownership of your Bitcoin or to receive funds. However, this naming isn't just outdated; it's risky, especially with quantum computing looming on the horizon.
Quantum computers pose a significant threat to the cryptographic methods securing Bitcoin wallets, specifically the Elliptic Curve Digital Signature Algorithm (ECDSA)—the algorithm Bitcoin uses to securely create digital signatures proving ownership. Quantum algorithms like Shor's algorithm could potentially derive a private key from its corresponding public key exponentially faster than classical computers. Think of your private key as your password—it must remain secret. Your public key acts more like your username, publicly identifying your account. But unlike a username, sharing your public key openly may become a severe risk once quantum computing matures.
However, there is some good news. Bitcoin unintentionally provides some quantum resistance through the common practice of keeping public keys hidden until funds are spent. Around 70% of existing Bitcoin addresses use a method called Pay-to-Public-Key-Hash (P2PKH), introduced by Bitcoin's creator, Satoshi Nakamoto. With P2PKH, public keys remain hidden until funds are spent, providing partial quantum protection for coins that haven't moved yet, as per our earlier analogy, it’s as if with P2PKH even your full username is hidden and only your initials are revealed. We should preserve this advantage—whether by luck or genius, Bitcoin's design partially safeguards users against future quantum threats.
If we continue calling these keys "public", we imply they can always be safely shared. This creates a false sense of permanent security, ignoring evolving technological threats.
So, what's a better name?
Let's shift our vocabulary and call it a "verification key". This clearly communicates its primary purpose: verification of signatures and transactions. It avoids giving users the false impression that it's safe to share indefinitely. Calling it a verification key reminds users that its primary function is verification—not unconditional public exposure.
Renaming the key isn't about spreading panic; it's about clarity. Users deserve clear, actionable information about their risks. By adopting better terminology, we encourage safer habits, such as minimizing address reuse and unnecessary exposure of keys.
Practical steps users can take today include limiting address reuse. By doing this, you reduce the risk of unnecessarily exposing your keys, improving your security as quantum threats grow.
Cryptocurrency has always aimed to decentralize control and empower users. Let's continue this by clearly informing people about their security. Quantum computing is coming, and our language must reflect this reality.
Let's retire "public key" and start honestly discussing "verification keys". Clarity today means safer cryptocurrency practices tomorrow.