Glassnode warns: 31.2% of Bitcoin supply faces quantum risk

Glassnode points out that 31.2% of the Bitcoin supply faces potential risks in quantum computing.

On-chain analytics company Glassnode issued a warning that 31.2% of the Bitcoin supply is currently associated with addresses where public keys are disclosed. This situation may become critical if sufficiently powerful quantum computers emerge in the future. The discovery drew attention to a structural vulnerability in the Bitcoin network that has existed since the birth of the protocol.

The meaning of 31.2% data

Bitcoin addresses are divided into many types, and not all addresses hide their underlying public key. The pay-to-public key (P2PK) output, as well as any address where a transaction has been sent and its public key has therefore been broadcast to the network, are referred to by researchers as having an "exposed public key." Glassnode's analysis shows that 31.2% of circulating supply is held in such outputs.

This distinction is important because Bitcoin's security model relies on two separate encryption layers. The first layer is a hash function, which protects addresses where funds have never been sent; the second layer is the Elliptic Curve Digital Signature Algorithm (ECDSA), which protects private keys after the public key is known. The address with the exposed public key has passed the first layer of protection, which means that there is only one line of defense between the attacker and the funds.

This is not a new observation. Some of the coins found in the P2PK output date back to 2009 and 2010, the Satoshi era, when the address format was the default setting of the protocol. For years, questions about where these coins will go as computing power improves have been circulating among cryptographers and Bitcoin developers. Glassnode's data provides a specific scale-up quantification of this exposure, which is useful for assessing the scope of any future remediation measures. In addition, the recent activation of one of the oldest Bitcoin wallets is a reminder that coins locked in early address formats are still an active topic on the Internet.

Why public key exposure is relevant to quantum risk discussions

In theory, a quantum computer capable of running Shor algorithm on a large scale can derive private keys from known public keys. However, current quantum hardware capabilities are limited and are far from enough to pose a threat to ECDSA in practice, and there is no reliable timetable for cryptographically meaningful quantum computers in public records. Therefore, Glassnode's warning is more a consideration within a risk framework than an imminent threat alert.

实际的担忧在于一种“竞态条件”：如果在比特币迁移到后量子签名方案之前，有人建造出了能够破解ECDSA的量子计算机，那么那31.2%拥有暴露公钥的供应量将比其余部分更加脆弱。而在标准P2WPKH或P2TR输出中、且从未用于发送资金的硬币，仍能从哈希函数层中获得保护，从而为紧急迁移争取额外的时间。

Glassnode此前曾利用链上数据将比特币市场中的结构性信号与短期噪音区分开来，而这一量子暴露指标也遵循相同的方法论：测量UTXO集合的实际状态，而非进行推测。

对比特币持有者和网络的意义

对于个人持有者而言，直接的含义很简单：持有在从未广播过交易的地址中的硬币，特别是原生SegWit（bc1q）或Taproot（bc1p）输出，仍保留着哈希函数的保护层。每次花费后将资金转移到新的、未使用过的地址，是标准的比特币卫生习惯，能直接降低此类风险的暴露度。

At the network level, the migration to backward quantum cryptography requires soft or hard forks, and a broad consensus among developers and miners, a process that will take years even if the timeline for quantum threats becomes clearer. The 31.2% ratio provides protocol developers with a specific yardstick to determine how much supply needs to be considered in any such upgrade. Coins in exposed output that cannot be contacted by the owner (including coins considered missing and early miner rewards) further increase the complexity of the calculation.

Difficulty adjustments in the Bitcoin network and incentives surrounding mining are not affected by public key exposure; if this vulnerability ultimately becomes a substantial issue, it will target specific UTXOs rather than consensus mechanisms. On-chain data is increasingly becoming the main tool for revealing Bitcoin network risks before they turn into market events, and Glassnode's quantum exposure indicators are in line with this trend. The key question now is whether the Bitcoin development community views the 31.2% ratio as a catalyst for accelerated quantum research or as a background issue to review as quantum hardware advances further.