Brains mining pool CEO Eli Nagar said in an analysis published on April 12 that the 2021 Taproot update is a setback from a quantum security perspective.
Nagar made the statement based on what was revealed by a recent Google Quantum AI study, as reported by CriptoNoticias. The research reduced the resources required to compromise the encryption that protects the signatures of Bitcoin transactions by up to 20 times.
Bitcoin’s latest update, “Taproot,” actually made things worse from a quantum perspective. Expose sensitive information and give quantum attackers unlimited time to operate.
Eli Nagar, CEO of Brains.
he paper Google classifies Pay to Taproot (P2TR) addresses, the format introduced by Taproot, as follows: Quantum vulnerabilities in the same category as Payment to Public Key (P2PK) formatsthe oldest on the network.
Why is Taproot vulnerable?
The technical reason is design. P2TR addresses store their public keys directly on-chain from the moment they receive funds. This means that any actor monitoring the network have permanent access to the public keyThere is no need to wait for users to make transactions.
This revelation is relevant to quantum threats because Scholl’s algorithm, runnable on a sufficiently powerful quantum computer, can use its public key to derive the corresponding private key and access funds.
Unlike other formats where the key is only exposed at the time of use,P2TR allows potential attackers to work without limit.. This also allows for “save today, decrypt later” attacks, where an attacker takes vulnerable information today and decrypts it in the future.
As reported by CriptoNoticias, data from the developer’s on-chain analytics platform known as Wicked. P2TR address has 100% of 205,581 BTC exposedthe same as the 1,716,320 BTC of a P2PK address from the Satoshi era. In total, approximately 6.9 million BTC (34.58% of the supply, approximately $500 billion) have public keys visible on-chain.
Adoption of tap root address in Bitcoin
Mr. Nagar further pointed out that: Taproot accounted for 21.68% of all Bitcoin transactions in 2025noted that the increased use of Taproot addresses will further expand the amount of potentially vulnerable BTC.
However, this figure stands in contrast to the current usage of this format. According to Clark Moody platform data from the past 30 days, Taproot Only 10.83% of trading volume There are 4,558,390 outputs and more than 20 million outputs in SegWit v0, the most used format on the network.
Taproot addresses peaked in adoption after the launch of the Ordinals protocol in 2023, when they were used to register arbitrary data on-chain. Once the boom died down, the format fell into disuse and is now one of the least used formats in the ecosystem.
This reduction in usage does not eliminate the quantum problem that Nagar poses, but rather limits it given the vulnerability that exists. For this reason, as reported by CriptoNoticias, Olaoluwa Osuntokun, CTO of Lightning Labs, published a proof of concept on April 8th aimed at precisely securing the Taproot wallet’s vulnerabilities and transforming it into a post-quantum wallet.
In this context, the debate regarding quantum threats to Bitcoin remains unresolved and there is no unified answer. Some ecosystem players believe the risks are decades away, while others point out that deadlines are compressing faster than expected and that the window for preparation is narrower than the community expects.
