Christopher Smith, co-founder and CEO of Quantus Network, warns that sufficiently powerful quantum computers could recover private keys from public keys revealed on blockchains.

Attack method and immediate consequences

Smith explains that an attacker would not need to breach a wallet device or internal exchange systems to steal funds via key reconstruction.

Instead, reconstructed private keys would enable creation of transactions that appear legitimate on the blockchain, moving assets without traditional traces of intrusion.

Such compromises would be practically indistinguishable from ordinary key theft, and incident responders might attribute them to routine access leaks.

Primary targets and sectors at risk

Among priority objectives Smith lists administrative keys controlling USDT, which could allow an attacker to mint tokens and place them onto markets before operations stop.

• Administrative keys for stablecoins and token issuance systems.
• Hot wallets used by cryptocurrency exchanges and custodial services.
• State and military systems that rely on current public-key cryptography.

Likelihood and prior warnings

Smith assesses the probability of such a threat materialising by 2028 at 50%, reflecting uncertainty about quantum hardware progress and cryptographic resilience.

Vitalik Buterin has previously issued similar warnings that quantum advances could compromise Bitcoin and other blockchain cryptography within comparable timeframes.

The concern highlights the need to evaluate post-quantum cryptographic upgrades for critical keys and infrastructure across the crypto ecosystem and beyond.