Bitcoin Quantum-Safe Spend Confirmed on Mainnet
Bitcoin (BTC)
Editor:
Eugene Serbin
Cvj.ai reports that a landmark Bitcoin transaction confirmed on August 26 demonstrated a quantum-resistant spending method without requiring a protocol upgrade. The transaction, included in block 964,199, utilized a construction by StarkWare researcher Avihu Levy and was submitted directly to miner MARA via its Slipstream service. This approach shifts security from elliptic-curve signatures to hash-based methods, leveraging the delay before a public key is revealed.
StarkWare noted the method works for addresses where the public key remains concealed, but it does not protect coins with visible keys like older pay-to-public-key outputs or Taproot addresses. The transaction was nonstandard under default node policy, requiring direct submission to bypass the public mempool. StarkWare estimated the computational cost at several hundred dollars, while open-source estimates suggest $75 to $150 for some cloud-GPU search phases.
Approximately 7 million BTC remain potentially vulnerable because their public keys are already visible through older formats or address reuse. StarkWare CEO Eli Ben-Sasson emphasized that the test proves workable approaches exist but warned that broader soft-fork solutions are still needed. He stated that the main task remains building a migration path before quantum hardware becomes capable of threatening exposed keys. Institutional efforts are already underway, with BlackRock, Coinbase, and Strategy forming the Bitcoin Security Consortium to pledge $15 million over three years for security research.
How the market reacted
Whalio's own Binance spot order flow for BTC, measured when this story was written up on 28 August 2026. Not the outlet's figures.
BTC is trading at $80,249.58 with a 1-hour buy ratio of 56.6%, indicating immediate short-term buying pressure. However, the 4-hour buy ratio sits at 50.1%, showing a neutral balance between buyers and sellers over a slightly longer timeframe. The 24-hour buy ratio has dropped to 45.2%, suggesting that buying interest is fading over the full day. Volume delta reflects this shift, with a positive $5,483,304 in the last hour contrasting sharply against a negative $123,102,218 over 24 hours. The cumulative volume delta (CVD) for the 24-hour close is -$119,598,057, confirming that net selling has dominated the day's activity. Spot volume reached $1,297,370,375 with nearly 5 million trades, but net buying occurred for only 5 of the 24 hours.
The latest daily buy ratio of 46.7% sits at the 18th percentile of the last 322 days, against a median of 49.2% - weaker buying than most days.
Twenty-four hours later
What BTC did over the 24 hours after the story broke. The market moves for its own reasons; this is what happened, not what the story caused.
Was that an ordinary day?
The same Binance spot measurements for BTC, averaged over the days leading up to the story.
Over the preceding week, the 7-day average buy ratio was 51.1%, meaning today's 24-hour ratio of 45.2% is 5.8 points below the weekly norm. Trading volume today was 0.65x the weekly average, indicating a quieter day than usual. The coin has gained 9.9% over the past 8 days, with a total volume delta of +$171,556,665 for that period. While the weekly trend shows net buying across 5 of 7 days, today's lower volume and negative delta suggest a pause in that momentum. This represents an unusual day for the coin relative to its recent average activity levels.