Satoshi Nakamoto’s Bitcoin could be among the first major targets of a future quantum attack because many of the earliest units sit in addresses where their public keys are already exposed.

Bitcoin security researcher Justin Drake warned in a recent interview with analyst Denis Liu that this vulnerability does not mean users should panic, as BTC held behind hashed addresses can remain protected until they are spent.

Satoshi’s Early Coins Face a Different Risk

The September 21 interview focused on roughly 1 million BTC mined by Satoshi across 20,000 addresses. Drake explained that the units were mined in 50-BTC blocks, with each address holding one block reward.

“All of these early Bitcoin addresses are raw pub keys,” Drake told Liu. “There isn’t this hashing step, and so they’re all vulnerable.”

He described Satoshi’s holdings as a potential target for “the operator of a quantum computer,” putting them in a different position from BTC that has never been spent from a hashed address.

For ordinary holders, the security issue is tied to spending. A Bitcoin address generally contains a hash of its public key rather than the key itself. But once the cryptocurrency is spent, the public keys become visible to everyone.

The security researcher advised users to send change to a fresh address whenever they spend Bitcoin. If the assets stay in a new address and are never spent, their public key has not yet been exposed.

“Your public key is not revealed publicly when you send funds to a fresh address,” Drake explained. “It’s only revealed publicly the moment you spend from that address. So, so long as you put Bitcoin in a fresh address and you don’t spend, then you’re actually fine.”

He also pointed out that even the fastest quantum machines discussed in current research would need time to crack cryptographic keys.

Furthermore, he urged holders not to rush into post-quantum cryptography “which is still being developed.” According to him, early upgrades could introduce bugs, while scammers could also exploit the fear by sending fake messages claiming that holders must immediately move to a “post-quantum secure” wallet.

Bitcoin Developers Are Already Testing Solutions

As CryptoPotato reported in August, a quantum-resistant Bitcoin transaction reached mainnet late that month using MARA’s private SlipStream mempool and a system called Quantum Safe Bitcoin.

The approach worked without changing Bitcoin’s consensus rules, although its use is currently limited to private mempools.

A separate proposal, BIP-361, published in April, would gradually freeze Bitcoin addresses considered vulnerable to quantum attacks. The proposal would first stop users from sending BTC to older address types, followed by a stricter cutoff two years later that would prevent remaining legacy wallets from sending funds.

There is a disagreement over how much Bitcoin is really exposed. In April, analyst James Check put the credible Satoshi-era target at 1.716 million BTC, rather than the 6.9 million BTC figure often cited in broader discussions about exposed keys.

He argued that while a complete sale of those assets would put downward pressure on the market, it would not necessarily produce a catastrophic outcome.

Source: CryptoPotato