A pivotal discussion initiated recently on social media platform X when renowned analyst Willy Woo released his “BEGINNER’S GUIDE TO ACHIEVING QUANTUM SECURITY.” He urged Bitcoin enthusiasts to transition their assets from Taproot addresses (bc1p) to more traditional SegWit (bc1q) or other older formats like P2PKH/P2SH, recommending they hold their coins until robust post-quantum tactics are in place.

Strategies for Ensuring Bitcoin’s “Quantum Security”

“Previously, the focus was primarily on safeguarding your PRIVATE KEY. However, with the looming threat of potential quantum computing capabilities, attention must also be directed toward your PUBLIC KEY. Advanced quantum algorithms can, in theory, derive the private key from its corresponding public key. The recently introduced Taproot addresses (which start with “bc1p”) are especially vulnerable since they incorporate the public key directly into the address,” Woo elaborated on November 11.

The crux of his argument is based on fundamental differences in Bitcoin’s scripting types: Taproot (P2TR) directly links the public key within the address output, while legacy types like P2PKH/P2SH and SegWit P2WPKH secure the public key by only revealing it during the transaction process. This key distinction could be critical in an era where quantum computing could theoretically yield private keys from exposed public keys. Other independent findings confirm that P2TR does indeed include the public key in the output, unlike P2PKH, which conceals it until a transaction is initiated.

Woo’s immediate recommendation is straightforward: transfer unspent transaction outputs (UTXOs) to a bc1q (or “1”/“3”) address, use it for receiving, but above all, “never send BTC from this address” until quantum-resistant upgrades are implemented. Users should make transfers to a new quantum-safe address during times of low traffic, thereby minimizing exposure of the public key in the network: “Transfer your BTC when the network is less congested, keeping in mind that revealing the private key is necessary but temporary. It is improbable that a quantum adversary would exploit this fleeting vulnerability to steal your coins.”

He cautioned that outputs using historical P2PK formats are particularly threatened, suggesting that coins with a history of transactions may find themselves at risk. “Satoshi’s 1 million coins, which are stored in outdated P2PK addresses, may not be secure unless future updates are implemented,” he noted, mentioning that exchange cold storage and financial products could achieve quantum resilience contingent on preemptive steps taken by their custodians.

Woo anticipates that by “2030 and beyond,” a significant milestone termed “Q-Day” may emerge, wherein quantum computing variables reshape the entire digital landscape, while emphasizing that measures for quantum resistance are already emerging in the broader arena of cryptographic technologies.

Jonas Schnelli, a previous maintainer for Bitcoin Core, concurred with the general hygiene advice but challenged the terminology. He termed Woo’s approach as a careful strategy for unspent coins—“While P2PKH secures coins for years, Taproot exposes the public key instantly,” he stated, but dismissed the term “quantum safe.”

In Schnelli’s perspective, once any transaction is initiated, “your public key enters the mempool, making it accessible for quantum hackers. They could potentially break your encryption and conduct a double-spend before your transaction is confirmed (in roughly 10 minutes).” He concluded, “This is a wise preventative measure, not the ultimate solution.”

At the time of this report, Bitcoin was trading at $104,693.