The first sign that quantum computing has broken modern cryptography probably won’t be a splashy theft of Satoshi Nakamoto’s dormant Bitcoin. It could just be a wave of unrelated crypto wallet breaches with no trace of how an attacker did it, according to the founder of blockchain startup Quantus.
“When someone cracks your key, you don’t get a memo saying how they did it,” Christopher Smith, CEO and co-founder of Quantus Network, told Cointelegraph. A sufficiently powerful quantum computer could derive a private key from public keys exposed onchain, allowing an attacker to move funds without compromising a wallet, device or exchange’s internal systems.
This makes the arrival of “Q-day” — a hypothetical future moment when quantum computers become powerful enough to break standard public-key cryptography — unusually difficult to detect. In a theft involving a highly secure organization, “the only forensic evidence would be that there was no breach,” Smith said.
Smith’s warning comes as advances in quantum algorithms have reduced estimates of computing resources needed to attack the elliptic-curve cryptography used by major blockchains.
First target may not be Satoshi’s Bitcoin
Much of the fear around Q-day in crypto is what will happen if a quantum computer cracks the keys securing Satoshi Nakamoto’s estimated Bitcoin holdings, worth $63 billion at the time of writing, which could be suddenly dumped on the market.
However, Smith said the first targets may be military systems and state secrets, while crypto attackers could go for even more valuable keys.
“If I’m focusing on blockchain, what’s the single most valuable key? It’s probably Tether’s minting key,” Smith said. A quantum attacker could mint tokens out of thin air from an administrative wallet and dump them on the market before the issuer could respond, he added.
USDT is a multi-chain stablecoin, and some of the networks on which it is deployed are already actively working on post-quantum migration.
Related: Jim Cramer plans to sell his Bitcoin over quantum fears as BTC rises 1.6%
Another theory is that attackers make a quieter opening move.
Sean Cheetham, a security researcher at Blockchain Capital, said an attacker would more likely target hot wallets at exchanges “that aren’t going to ring alarm bells rather than stealing Satoshi’s coins.”
Smith said an attacker may disguise a quantum theft as an ordinary compromise.
