Almost 10% of the total bitcoin supply could be at risk in the event of a real breakthrough in quantum computing. This conclusion was reached by Glassnode analysts, who assessed which types of BTC addresses already reveal public keys and could theoretically become vulnerable if modern cryptography is broken.
This concerns about 1.92 million BTC. This group includes early Satoshi-era coins, old multisig structures, and modern Taproot addresses, where the public key is revealed due to the architecture itself.
Satoshi-Era Coins Are at Risk
The largest portion of potentially vulnerable BTC relates to early P2PK addresses, which were used in the first years of the network. At that time, bitcoin did not yet use modern address protection standards, so the public key was published directly on the blockchain.
Glassnode estimates the volume of such coins at about 1.1 million BTC. This is about 5.5% of the total bitcoin supply.
Additionally, analysts identified about 620,000 BTC from the early network period and about 200,000 BTC in Taproot addresses. Together, they make up almost 10% of the “structurally vulnerable” supply.
The Problem Is Not Theft Today, but a Future Breakthrough
Currently, these coins are not under immediate threat. For a real attack, a quantum computer would need to learn to break the elliptic cryptography on which bitcoin is built.
According to Ark Invest, this would require about 2,330 logical qubits and a huge number of quantum operations—from tens of millions to billions of computational steps.
Existing quantum systems do not yet have such capabilities. But the fact that some BTC already reveal public keys is making the market discuss the transition to post-quantum protection in advance.
Taproot Unexpectedly Also on the Risk List
The mention of Taproot attracted special attention. This address format was long considered one of bitcoin’s technological steps forward, as it improved transaction privacy and efficiency.
However, Glassnode notes that Taproot also reveals the public key in certain types of use. Because of this, about 1% of the total BTC supply in such addresses also falls into the potentially vulnerable category.
This does not mean that Taproot is “broken.” But it shows how complex the discussion about the future security of the network is becoming in the era of quantum computing.
Almost 70% of BTC Still Considered Protected
Despite the big numbers, most bitcoins remain relatively safe. Glassnode estimates the share of protected supply at about 69.8% or about 14 million BTC.
These are coins where the public key has not yet been directly revealed on the blockchain. As long as the owner does not spend such BTC, a potential attacker cannot see the key and cannot even theoretically try to guess the private part.
Similar estimates were previously published by Ark Invest. They believed that about 65% of the supply is not subject to quantum risk with the current network structure.
Another 20% of Supply Vulnerable Due to Poor Storage Practices
Analysts separately note the so-called “operational vulnerability.” This is another about 4.12 million BTC or more than 20% of the supply.
This is not about address structure, but poor key management: reusing addresses, old storage schemes, or weak infrastructure.
According to Glassnode, this segment is the one the market can reduce the fastest. For this, exchanges, custodians, and large holders need to change asset storage practices and switch to more secure address standards.
Large Companies Already Under Scrutiny
Glassnode also assessed the level of potential vulnerability among large corporate bitcoin holders.
According to analysts, almost 100% of BTC at Robinhood, WisdomTree, and Franklin Templeton are in the potentially vulnerable category. For Revolut, the figure reaches 99%.
At Grayscale, about half of BTC reserves fall into the risk group, while at Fidelity, only about 2% of reserves are considered vulnerable.
Exchanges Also Unevenly Distributed
Among crypto exchanges, the situation is even more different. Glassnode estimates the potential vulnerability of BTC at Coinbase at about 5%. For Binance, the figure is much higher—about 85%. And for Bitfinex, analysts attribute almost all BTC reserves to potentially exposed.
This difference is primarily due to how platforms organize coin storage and how actively they use repeated addresses.
Market Again Discusses Post-Quantum Protection
Following the Glassnode report, crypto industry participants have again started actively discussing BIP-360 and other network upgrade options.
One proposal is the Pay-to-Merkle-Root format, which should eliminate some vulnerable Taproot scenarios. At the same time, BIP-360 itself does not add full post-quantum signatures, but only changes the architecture of some BTC spending mechanisms.
The main problem is that the transition to a new security model for bitcoin will be an extremely complex political and technical process. Especially if it concerns old Satoshi-era coins.
Industry Again Discusses the ‘Collect Now, Crack Later’ Risk
A separate concern is the scenario the industry calls ‘collect now, crack later.’ Its essence is simple: attackers can already save public keys and old transactions, hoping to use them once sufficiently powerful quantum systems appear. Because of this, even a distant quantum breakthrough is already influencing the discussion of bitcoin’s long-term architecture.
What’s Next?
For now, quantum computers are not able to threaten bitcoin directly. But Glassnode shows that the problem is gradually ceasing to be purely theoretical.
The closer the market gets to the era of real quantum computing, the more important the issue of migrating old addresses, changing storage standards, and preparing the network for post-quantum cryptography becomes.
Especially given that almost 10% of the BTC supply is already considered structurally vulnerable in the event of a future technological breakthrough.
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