$147.41/month. Passive income, starting today.

Antminer S21 — one of the most efficient Bitcoin miners available right now. Brand new units, ready to ship from our Hong Kong warehouse.

1️⃣Hashrate: 151 TH/s
2️⃣Power: 2645W
3️⃣Efficiency: ~17.5 J/TH

💵 Price: $860

Host with us — pay only $830

Zero setup. Zero hassle. Just plug in your profit.

*Monthly profit estimated before electricity costs.

Ready to order? Contact our manager:

🖇 sales@uminers.com
💬 WhatsApp
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📞 +852 64825025
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⚡️Bitdeer has launched a new line of ASIC miners — SEALMINER A4

Three models — for different needs and operating conditions:

0️⃣ A4 Ultra Hydro — 886 TH/s | 9.45 J/TH | hydro cooling
0️⃣ A4 Pro Hydro — 680 TH/s | 10.9 J/TH | hydro cooling
0️⃣ A4 Pro Air — 336 TH/s | 10.9 J/TH | air cooling

All models maintain stable operation in temperatures ranging from -20°C to +55°C.
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🪙 Zero-day vulnerability discovered in Bitcoin mining — it has existed since day one

Researcher Loïc Morel has uncovered a bug in Bitcoin’s difficulty adjustment mechanism.

Every 2016 blocks, nodes calculate the new difficulty by comparing the timestamp of the first and last block in the period. Because of this, they only measure 2015 intervals instead of 2016 — this is known as an “off-by-one” error.

The real issue: difficulty adjustment periods don’t overlap. This opens the door to a Time Warp attack.

An attacker with majority hash power could:

Set minimal timestamps on all blocks in the period (except the last one);
Set the maximum allowed timestamp on the final block.

As a result, the measured period appears longer than it actually was, causing the difficulty to drop. By repeating this, the attacker could theoretically mine up to 6 blocks per second.

A fix has already been proposed via soft fork BIP-0054. It introduces a rule that the timestamp of the first block in a new difficulty period cannot exceed the timestamp of the last block of the previous period by more than 2 hours.

This critical bug has existed in Bitcoin’s code for 17 years.
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