Bitcoin eased and is trading near $83,150 as the market digests another round of headlines about the quantum threat. Such warnings appear every few months, but three developments converged this week: the cost of quantum-resistant transactions fell, a new privacy design was published, and a major custodian disclosed plans to protect its assets. I believe it is important to distinguish real risk from noisy headlines by time horizon, because that timing is what matters for price.

The risk itself is real. Bitcoin wallets are protected by elliptic-curve cryptography in which a private key is mathematically linked to a public key. As experts note, a sufficiently powerful quantum computer running Shor's algorithm could, in theory, derive the private key from the public one, forge signatures, and drain funds. The industry calls the arrival of such a machine "Day Q." No such computer exists today, and timing estimates vary widely, though they are steadily being revised closer, which is why preparations have accelerated. The most vulnerable coins are those whose public keys have already been revealed.

The most concrete development this week concerns the cost of a workaround. StarkWare, which produced the first quantum-safe Bitcoin transaction on mainnet in August, said an open contest launched on September 16 with Yukon Research and Eigen Labs reduced the estimated cost of such a transaction from roughly $320 to about $67 in a single week—a near-80% decline. The leaderboard features participants using AI models.

Does that mean Bitcoin is now quantum-safe? No. A full answer requires a protocol upgrade to post-quantum signatures, and because governance is decentralized, such development, testing, and deployment take years; the community has only recently begun to tackle the problem seriously.

I would not rule out that quantum headlines remain background noise rather than the trigger for sustained selling, with Bitcoin prices continuing to be driven primarily by macro data and capital flows. Pressure on Bitcoin will become real only if verified evidence appears that the time to Day Q has shortened materially; until then, custodians' preparations are likely to bolster institutional confidence rather than undermine it.

Technical picture for Bitcoin and Ethereum

Bitcoin: buyers are targeting a return to $86,400, which opens a direct path to $89,000 and then to $92,100; a break above that level would signal attempts to restore the bull market. On the downside, expect buyers at $83,300. A move below that area could quickly drag BTC toward $81,600. A farther downside target is $79,400.

Ethereum: a confirmed hold above $2,710 opens a path to $2,770. The farther target is the high near $2,872; a break above that level would indicate strengthening bullish sentiment and renewed buyer interest. On the downside, expect buyers at $2,648. A drop below that area could push ETH toward $2,578. A farther downside target is $2,486.

What we see on the chart:

- Red lines indicate support and resistance levels where either a price slowdown or active growth is expected;

- Green lines indicate the 50-day moving average;

- Blue lines indicate the 100-day moving average;

- Light green lines indicate the 200-day moving average.

A crossover, or a price test of moving averages, typically either halts the move or sparks fresh market momentum.