Arkham Uncovers $3.5B Bitcoin Theft from Chinese Mining Pool Stolen in 2020, Largest Theft Ever

A massive Bitcoin theft from 2020 has surfaced nearly four years later, and it’s now being called the largest crypto heist ever uncovered.

Key Takeaways:

• Arkham has revealed an undisclosed 2020 hack of 127,426 BTC from Chinese mining pool LuBian.
• The attack exploited weaknesses in LuBian’s private key system, with over 90% of its BTC drained in a single day.
• LuBian attempted to contact the hacker via Bitcoin’s OP_RETURN feature.

On Saturday, blockchain analytics firm Arkham Intelligence reported that 127,426 BTC, valued at around $3.5 billion at the time and nearly $14.5 billion today, was stolen from Chinese mining pool LuBian in December 2020.

LuBian rose quickly in early 2020, becoming the sixth-largest mining pool on the Bitcoin network by mid-year.

Its website promoted it as “the safest high yielding mining pool in the world.”

By February 2021, LuBian had disappeared without explanation, fueling speculation that it was either shut down by authorities or quietly converted into a private pool.

Arkham’s investigation points to a more dramatic exit: a hack that drained the pool’s holdings.

“They appear to have been first hacked on December 28th, 2020 for over 90% of their BTC,” Arkham wrote.

The following day, attackers siphoned off another $6 million in BTC and USDT from a LuBian-linked address on the Bitcoin Omni layer.

The firm believes the Bitcoin theft stemmed from vulnerabilities in LuBian’s private key generation system, which may have allowed brute-force attacks.

While 11,886 BTC, worth roughly $1.35 billion, remains untouched in LuBian’s wallet, none of the stolen coins have moved since July 2024.

Interestingly, LuBian attempted to communicate with the attacker using Bitcoin’s OP_RETURN feature.

BREAKING: ARKHAM UNCOVERS $3.5B HEIST – THE LARGEST EVER

LuBian was a Chinese mining pool with facilities in China & Iran. Based on analysis of on-chain data, it appears that 127,426 BTC was stolen from LuBian in December 2020, worth $3.5 billion at the time and now worth… pic.twitter.com/PnIOKgMt0i

In two transactions, the team wrote: “To the whitehat who is saving our asset, you can contact us… to discuss the return of asset and your reward.”

The message included an email address, but it’s unclear if the hacker ever replied.

While the Mt. Gox collapse involved more BTC, the LuBian breach is the largest confirmed crypto theft by value at the time of the incident.

Crypto investors lost over $2.2 billion to hacks, scams, and breaches in the first half of 2025, driven largely by wallet compromises and phishing attacks, according to CertiK’s latest security report.

Wallet breaches alone caused $1.7 billion in losses across just 34 incidents, while phishing scams accounted for over $410 million across 132 attacks.

Two major incidents, including Bybit’s $1.5 billion hack in February and Cetus Protocol’s $225 million exploit in May, skewed the year’s losses upward, together accounting for nearly $1.78 billion.

Without these, losses align more closely with previous years at around $690 million.

Ethereum remained the primary target, suffering over $1.6 billion in losses across 175 events.

The report also pointed to rising sophistication of phishing schemes and ongoing risks from social engineering, urging crypto users to verify links, avoid suspicious sites, and use hardware wallets.

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