- CoinShares has presented a report that objectifies the discussion about quantum computer attacks that has been inflated with false risks.
- The analysis shows: Only a very small part of the Bitcoin supply would be realistically vulnerable – and even then only in the distant future.
The focus of the investigation is the question of which Bitcoin addresses would theoretically be vulnerable to future quantum computers. The result is not surprising: only wallets whose public key is already publicly visible are vulnerable.
This primarily includes old P2PK addresses from the early years of the network as well as wallets that have reused addresses multiple times. Modern address formats such as P2PKH, P2SH or Taproot are considered significantly more secure because the public key is only revealed when a transaction is issued.
CoinShares quantified The total amount of Bitcoins stored under such old addresses is around 1.63 million.
This number causes the usual excitement on social media, but the Coinshares analysis makes it clear: the overwhelming majority of all Bitcoins are untouchable for the foreseeable future because even quantum computing models considered “optimistic” would take centuries to break the underlying cryptography.
Around 10,000 Bitcoins would be at risk
The crucial point of the study is the differentiation between theoretically exposed and realistically vulnerable coins. CoinShares comes to the conclusion that only around 10,230 BTC – distributed across medium and large wallets – would represent an economically sensible target. This amount is negligible compared to the amount of Bitcoins in circulation and would not trigger a systemic shock even in an emergency and assuming success.
An attack of this magnitude would be more akin to a large but market sale. The technical hurdle is also enormous. According to current research, around 13 million fault-tolerant qubits would be needed to crack a single Bitcoin key within a day.
Google’s currently most powerful chip, “Willow,” has 105 qubits. But you need around 124,000 times more to get the necessary 13 million qubits. Even Google will probably have to crack this for a while.
Preparation and composure
The publication sparked a lively debate in the Bitcoin community. While representatives like Michael Saylor and Adam Back classify the risk as greatly exaggerated and point to the long time horizon, other voices like Charles Edwards call for early preparation for post-quantum cryptography. The discussion is less about acute dangers and more about the question of how proactively Bitcoin should react to future technological developments.
At the same time, the first experiments with quantum-resistant signatures such as ML‑DSA are already running in test environments. However, a possible migration in the Bitcoin protocol would be a long-term process that requires widespread approval and extensive testing.
Technically relevant – currently harmless
The CoinShares analysis brings much-needed clarity to a debate that has recently been dominated by FUD and exaggerated warnings. Although there is a theoretical quantum risk for certain legacy addresses, no, this risk is neither acute nor systemic.
The realistically endangered amount of around 10,000 BTC is small, and the technological gap to an actually dangerous quantum computer is huge and will not be overcome in the foreseeable future.
For Bitcoin this means: Stay vigilant, promote research – and don’t panic. Cryptography will continue to evolve, but Bitcoin has plenty of time to adapt.
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