Bitcoin's Quantum Risk Is Real - One Solution Might Start With Taproot

"Imagine waking up, checking your phone, and your bitcoin balance is zero. Not just your cold storage, your exchange balances too. Gone. Overnight, millions of UTXOs drained in a silent, coordinated attack. It sounds extreme, but this kind of event would be more than just theft. It would be a direct attack on Bitcoin's value, a public signal that its core cryptography is no longer secure."

"Not every attacker would act so loudly. A more self-incentivized one might take the opposite approach. With access to a quantum computer, they could quietly target older UTXOs, draining coins from forgotten or inactive wallets. Their goal would be to siphon off as much as possible before the rest of the world catches on. But whether the attack is loud or quiet, fast or slow, the end result is more or less the same."

"A quantum computer isn't just a faster version of computers we have today. It's a fundamentally different type of machine. For most tasks, it wouldn't be much faster than a regular computer. But for very specific problems, it would be powerful enough to break a lot. Bitcoin's digital signatures today, including Schnorr and ECDSA, rely on something called the discrete logarithm problem. Think of it as a kind of mathematical one-way street. It's easy to go one direction, but extremely hard to go back."

Roughly a quarter of all Bitcoin is exposed to quantum attack risk because public keys have been revealed on the blockchain. A capable quantum computer could break cryptographic signatures like Schnorr and ECDSA by solving discrete logarithm problems. Attack scenarios include loud, state-level attacks that drain many UTXOs to destroy trust, or quiet theft targeting older, forgotten wallets. Either outcome would invalidate core security assumptions and undermine Bitcoin's value. Quantum computers are not universally faster but are powerful for specific problems that threaten current digital-signature security. The theoretical possibility of such machines creates urgent systemic risk.

Read at Bitcoin Magazine