A warning has emerged that even if quantum computers reach a level capable of undermining today’s cryptography, the first sign in the cryptocurrency market may not be a large-scale theft of symbolic assets such as Satoshi Nakamoto’s bitcoin wallet. An analysis said an attack that looks like an ordinary wallet compromise with no clear explanation could happen first.

Cointelegraph reported on Aug. 10 that Christopher Smith, chief executive and co-founder of Qunters Network, pointed to the possibility that once quantum computers are powerful enough, attackers could calculate private keys using only public on-chain public keys and steal funds.

The key point is that, unlike conventional hacks, there may be no need to directly attack a wallet, smartphone or an exchange’s internal systems. Smith said that even if it is clear an attacker has broken a key, it may be difficult to identify a specific intrusion path. "If someone breaks your key, you don’t get a memo telling you how they did it," he said.

That is why, the analysis said, the so-called "Q-Day" feared by the industry may involve not only the moment quantum computers break encryption but also a difficult process of detecting the attack itself. Q-Day refers to a hypothetical point when quantum computers gain enough computing power to render widely used public-key cryptography ineffective. If a quantum attack occurs at a highly secure organisation, Smith said, "the only forensic evidence will be that there is no evidence of compromise."

The cryptocurrency market has long raised concerns that if Q-Day arrives, early bitcoin believed to be held by Satoshi Nakamoto would be attacked first. Smith said an attack does not have to start with the most famous wallet. He said attackers could first target keys tied to military systems or state secrets, and in the cryptocurrency market, keys with greater economic value could become priority targets.

He pointed to stablecoin issuers’ administrative keys as a representative case. Smith cited Tether’s issuance key as one of the most valuable single keys on a blockchain. If an issuance management wallet is exposed to a quantum attack, an attacker could generate tokens arbitrarily and release them into the market before the issuer does, he said.

In such a case, the attack could look far more like a normal account compromise than a large-scale bitcoin theft. Shaun Cheatham, a security researcher at Blockchain Capital, also predicted that rather than targeting Satoshi’s bitcoin, an attacker could first hit an exchange hot wallet that is more likely to avoid triggering alarms.

Smith also mentioned that a quantum attack could be disguised as an ordinary account takeover. From the outside, it could look as if someone lost a private key or a wallet was hacked, he said.

These concerns coincide with claims that existing quantum threat timelines could move forward as quantum algorithms and artificial intelligence develop at the same time. Google brought forward its post-quantum cryptography migration timeline to 2029 in March, reflecting research results that used AI. The decision was influenced by findings that elliptic-curve cryptography widely used in blockchain systems could be attacked with fewer physical qubits than previously expected. Roy Blackstone, CEO of Ngrave, also said existing quantum computer projections did not sufficiently take into account parallel advances in AI.

Even so, views differ widely on when quantum computers capable of breaking cryptography will emerge. Smith put the chance at about 50 percent that quantum computers will reach that level by 2028. Cheatham said it is very likely such technology will appear in the early 2030s, but put a relatively lower probability on an earlier timeframe. Michael Cotts, chief information security officer at the Solana Foundation, said it is difficult to predict a specific time and that there is effectively "no way to know."

Uncertainty remains over the timing of quantum computers, but the industry is forming a consensus that there is no reason to delay preparations.

The blockchain industry has already begun work to shift existing signature methods to post-quantum cryptography. Blackstone said that if major blockchains had not moved to post-quantum signature schemes, the damage would have been "catastrophic." Some networks that issue Tether are also reported to be carrying out post-quantum transition work.

Ultimately, what the cryptocurrency market must prepare for is not only the exact date of Q-Day. A bigger problem is that even if a quantum attack occurs, it may initially look like an ordinary wallet hack or key loss. With few traces left behind, how quickly exchanges, wallets and blockchain networks can detect anomalies and respond could determine the scale of damage.

How quickly major networks, wallets and exchanges switch to post-quantum security systems before the threat of quantum computers becomes reality is emerging as a key security task for the cryptocurrency market.