Almost 10% of all Bitcoins could be exposed to quantum attacks
According to data from analytics platform Glassnode, about 1.92 million BTC, or approximately 9.6% of the total supply of Bitcoin, are located at addresses that could theoretically be vulnerable if quantum computers one day manage to break through today’s cryptographic protection of Bitcoin. The reason for this is not how users store their coins, but certain types of Bitcoin addresses that, by design, reveal the public key. Among them are early Pay-to-Public-Key (P2PK) wallets from the period when the network was just launched, then Pay-to-Multisig (P2MS) addresses and the newer Taproot (P2TR) releases. The bulk of the potentially exposed amount relates to coins associated with Bitcoin’s creator, Satoshi Nakamoto. It is estimated that they account for around 1.1 million BTC or approximately 5.5% of the total supply. An additional 620,000 BTC originated from the early period of Bitcoin’s development, while about 200,000 BTC are located at Taproot addresses. Glassnode points out that some of this risk could be mitigated by the development of wallets, new standards for Bitcoin addresses, and changes in the way users manage their coins. At the same time, experts from ARK Invest emphasize that the issue of introducing post-quantum cryptography into Bitcoin should be viewed separately from the question of what to do with coins that could remain vulnerable. It is important to emphasize that there is currently no quantum computer that can crack Bitcoin’s cryptography. According to ARK Invest’s analysis, such an attack would require a quantum computer with about 2,330 logical qubits and the ability to perform tens of millions to billions of quantum operations, which today’s technology does not yet allow.
Source: cointelegraph
Most Bitcoins are not currently exposed to this risk
While the potential threat of quantum computers is often highlighted, data shows that the bulk of Bitcoin’s existing supply is not currently considered exposed to this type of risk. According to Glassnode, about 13.99 million BTC, or 69.8% of the total supply, are located at addresses whose structure does not reveal the public key before the coins are consumed. This is very similar to an estimate by ARK Invest, which previously stated that about 65% of the total amount of Bitcoin is protected against this scenario. On the other hand, Glassnode estimates that around 4.12 million BTC, or 20.6% of the total supply, are considered “operationally exposed”. Unlike structurally exposed addresses, the problem here is not in the design of Bitcoin scripts, but in the way wallets were used or keys were managed.
Source: cointelegraph
How exposed are large companies and crypto exchanges?
Glassnode’s analysis shows that the level of potential exposure also varies among large companies that hold Bitcoin. According to published data, the entire amount of Bitcoin held by Franklin Templeton, WisdomTree, and Robinhood is located at addresses that are considered structurally exposed. With Revolut, this share is about 99%, while with Grayscale it is about 52%. Fidelity stands out for its significantly lower exposure, which according to the analysis is around 2%. Similar differences are visible among crypto exchanges. Glassnode states that about 5% of Bitcoins on Coinbase are potentially exposed to this risk. With Binance, this share is approximately 85%, while for Bitfinex it is stated to be almost 100%. Analysts believe that some of this risk can be mitigated by better key management and the use of new addresses instead of reusing existing ones.
Source: cointelegraph
Why exposure is not the same for all Bitcoin addresses
Although it is often referred to as a percentage of the total supply, the actual exposure depends to a large extent on the
about the way Bitcoin addresses have been used over time. The problem appears only in
when the public key is discovered on the blockchain, which happens with certain types of
transaction or when reusing the address.
Because of this, two addresses that look similar at first glance may have completely different
level of exposure. Older formats and patterns of use, as well as repeated use of the same
address, increase the amount of data that is publicly available.
Source: cointelegraph
Technical solutions under consideration for future changes
There has been some discussion in the community about how to adapt Bitcoin to the potential development of quantum computers. One approach is to introduce post-quantum cryptography, which would replace or complement existing cryptographic algorithms. Proposals such as BIP-360, which includes new types of outputs designed to reduce dependence on current cryptographic assumptions, are also mentioned. Such changes do not introduce new digital signatures per se, but they do change the way transactions are structured. In practice, such changes would require the harmonization of wallet infrastructure, exchanges and user habits, which makes the process gradual and technically complex.
Source: cointelegraph
Conclusion
The data related to Bitcoin’s potential exposure to quantum computers is mainly based on the address structure and how public keys are revealed on the blockchain. Part of the offer falls into categories that are considered more sensitive due to the design of the outputs themselves or historical patterns of use, while the majority remains outside these groups. At the same time, analyses show that a significant portion of exposure can be reduced through changes in wallet infrastructure, address standards, and key management practices. In parallel, proposals are being developed that could change the cryptographic mechanisms within Bitcoin in the future. How quickly such changes will be implemented depends on the development of technology, but also on the way in which different parts of the Bitcoin ecosystem harmonize.