Consensus Is The Last Middleman: The Case For Quantum Money

What Happened

That work later inspired the 1984 protocol known as BB84, which launched quantum cryptography. In effect, the whole field grew out of an attempt to make unforgeable money.

Market Context

Stefano Gogioso and Daniela Herrmann made the argument during the latest BeInCrypto Experts Council. Their case rests on an idea older than crypto itself, and on a single law of physics.

Money Has Always Been a Story About Trust

Why It Matters

Quantum computers could one day break Bitcoin (BTC), yet the same physics could also build money that is impossible to forge. Two experts argue that quantum money, not the blockchain, may be the final form of digital cash.

A companion analysis asked when quantum computers might break Bitcoin. This piece asks the opposite question. What if the same technology builds something better than the money we use today?

Wiesner proposed money that could not be counterfeited, protected by physics rather than by a bank. It was the first real use anyone had imagined for quantum information.

Details

The answer begins with a line from Gogioso that reframes the debate. Consensus, he says, is “the last middleman.”

To see why, it helps to trace how money lost its trust in the first place.

Physical cash needs no middleman. A gold coin proves itself, and a buyer does not have to trust a bank, a ledger, or a network to accept it. Cash, however, cannot travel down a wire.

Digital money solved distance, but it brought the middlemen back. Every online payment now trusts an intermediary to confirm that the same unit is not spent twice.

Bitcoin answered that problem by replacing institutions with math and consensus. Thousands of computers agree on one shared history, so no central party is needed.

The idea of using physics instead of trust, however, is older than Bitcoin. It is older than the modern internet.

In the late 1960s, a Columbia University graduate student named Stephen Wiesner wrote a manuscript called “Conjugate Coding.” Journals rejected it, and it stayed unpublished until 1983.

Security From Physics, Not Secrecy

Classical cryptography rests on hard math problems. A code stays safe because solving it would take too long. Quantum cryptography works on a different footing.

Its guarantee comes from a physical law called the no-cloning theorem. Physicists William Wootters and Wojciech Zurek proved it in 1982. An unknown quantum state cannot be perfectly copied.

The mechanism is elegant. Any attempt to copy the state disturbs it. The forgery fails, and the tampering shows.

Gogioso has spent years turning that law into working tools. At an earlier BeInCrypto interview in Naples, he described keys that defend themselves. If someone intercepts a quantum key, it is destroyed in transit, and the receiver sees the protocol break.

On the Council panel, he pushed the idea to its limit.

“You can build applications that do not need to trust the very hardware they run on. You can literally commission the hardware from your attacker, and as long as the application passes its self-testing, you are guaranteed security. Worst case, it simply refuses to run. And this is provably impossible classically.”

Specialists call this device-independent cryptography. The security holds even if the manufacturer is hostile. That property matters because complex hardware is exactly where backdoors tend to hide.

Why Unforgeable Keys Become Money

The step from security to money is short. Cheating and forgery are the same problem in different words.

If you cannot copy a quantum state, you cannot counterfeit it. And a thing that cannot be counterfeited can serve as money.