USDC quantum security risk cited amid 813-qubit record
USDC (USDC)
Editor:
Eugene Serbin
Grafa.com reports that USDC faces long-term quantum security risks due to its broad infrastructure footprint. Circle stated that USDC spans 37 mainnet networks, each with distinct upgrade systems and security requirements. This warning follows a recent quantum circuit record of 813 logical qubits, which raises concerns about future attacks on blockchain signatures.
Circle advised developers to review their cryptography, check vendor dependencies, and prepare for key rotation. However, the 813-qubit record does not indicate that a quantum attack is currently possible or provide a specific date for one. The challenge extends beyond Circle because wallets, custodians, bridges, and blockchain networks must also support safer signing systems.
Circle can protect its own infrastructure but cannot change private keys or signature rules across networks like Ethereum and Solana. The report highlights that USDC may be only as secure as the weakest wallet, bridge, or blockchain supporting it.
How the market reacted
Whalio's own Binance spot order flow for USDC, measured when this story was written up on 3 September 2026. Not the outlet's figures.
USDC is trading at $1.00 with a 1-hour buy ratio of 45.2%, indicating slightly more selling than buying in the short term. The 4-hour buy ratio is 50.2%, showing a balanced market over a slightly longer timeframe. The 24-hour buy ratio is 49.0%, suggesting a near-even split in trading pressure over the day. Volume delta for the hour is -$7,581,564, reflecting net selling pressure in the immediate term. Over 24 hours, the volume delta is -$36,451,723, with a cumulative volume delta (CVD) of -$21,467,202 at close. This indicates that sellers have dominated the flow over the full day, despite the 4-hour balance.
The latest daily buy ratio of 49.8% sits at the 69th percentile of the last 281 days, against a median of 47.8% - ordinary for this coin.
Was that an ordinary day?
The same Binance spot measurements for USDC, averaged over the days leading up to the story.
Over the preceding week, the average buy ratio was 48.4%, with the latest day showing a slight increase of 0.6 points. Spot volume for the day was 0.68x the weekly average, indicating lower-than-average trading activity. There were zero days of net buying in the past week, contrasting with the mixed signals in the 24-hour data. The price change over eight days is +0.0%, showing no significant movement. This day is ordinary in terms of price stability but unusual in its lack of net buying pressure over the week, with a total volume delta of -$545,077,712.