A new report from quantum security firm Project Eleven warns that a quantum computer capable of breaking the cryptography securing Bitcoin and Ethereum could arrive by 2030, potentially earlier than expected.
The report says roughly 6.9 million Bitcoin, or one-third of total supply, and over 65% of all Ether sit in addresses vulnerable to quantum attack.
Unlike banks, blockchains have no fraud protection-once a wallet is drained, the loss is permanent.
The report highlights that while the internet sector has already begun adopting post-quantum encryption, the blockchain industry has barely started.
Bitcoin’s SegWit upgrade took over two years and triggered a contentious split; Ethereum’s proof-of-stake transition required six years. A quantum migration would be far more complex.
Even if 100% of Bitcoin block space were dedicated to migration, it would take 76 days to move all UTXOs to quantum-resistant addresses, and far longer in practice.
The report urges blockchain networks to conduct cryptographic inventories and deploy post-quantum security measures now, warning that time is running out.