Can Governments Shut Down Bitcoin or Altcoins With Quantum Computers?

(MotleyFool) The rise of quantum computing may soon give governments a means to crack down on Bitcoin and other types of cryptocurrencies. Information encoded in super “quantum” computers, known as qubits, exists in infinite states due to something called superposition, as there are infinite decimal numbers between 0 and 1, significantly enhancing their speed over binary computer systems. Governments could potentially decrypt digital currencies or launch hash attacks to take over their network for a regulatory shutdown with these machines.
It will take a 5,000 qubit quantum computer to penetrate Bitcoin’s encryption and solve for private keys. Right now, the most advanced quantum computers can only reach 66 qubits as their quantum states are very difficult to control. So the thought of any government’s quantum computers decrypting your crypto wallets should be the least of your worries for at least the next 100 years or so.
Cryptography is a field that overwhelmingly favors the defender and not the attacker. The quantum computing fear and uncertainty is pretty far away given its slow development and the Bitcoin network’s capacity to evolve to resist attacks, such as with encryption upgrades. Remember there are other priorities governments may want to use their quantum computers for, as many hacking and ransomware incidents happen beyond the world of Bitcoin still.
However, the same cannot be said for other, less securely developed altcoins with far lower network hash rates than Bitcoin. It would mean that even a less sophisticated quantum computer can launch 51% hash attacks (meaning they need only control 51% of the network mining power) against them. In the end, don’t be surprised if the U.S. Securities and Exchange Commission gets its hands on one and uses it to start shutting some of the regulatory delinquent cryptocurrencies down sooner rather than later.