article 💰🚨 The $3.5B Bitcoin Mega-Heist That Stayed Hidden for Years

In a shocking revelation, blockchain intelligence firm Arkham has retroactively uncovered what is now recognized as the largest cryptocurrency theft in history. The massive hack, which occurred in 2020, went unnoticed publicly for years — neither the victims nor the hackers ever disclosed it.

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The Hidden Hack

According to Arkham’s latest findings, the Chinese mining pool LuBian was targeted on December 28, 2020, when hackers successfully drained 127,426 Bitcoin (BTC) — worth roughly $3.5 billion at the time.

To put this into perspective: the stolen sum represented about 90% of LuBian’s total BTC holdings. The mining pool managed to salvage only 11,886 BTC by moving it into recovery wallets.

Despite the staggering scale of the theft, the incident was never reported publicly. Arkham’s research team only revealed it recently in their investigation.

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How the Hack Worked

In a rather unusual move, LuBian later sent 1,516 on-chain OP_RETURN messages to addresses linked with the hacker. These embedded notes cost the pool approximately 1.4 BTC in transaction fees.

Arkham analysts believe that the breach stemmed from LuBian’s flawed private key generation system:

Today, those stolen Bitcoin would be worth an eye-watering $14.5 billion — underscoring how critical robust cryptographic security and safe key management are for crypto holders.

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Bigger Than ByBit and Other Notorious Hacks

Until now, the February ByBit hack — which resulted in a $1.5 billion loss — had been considered the largest crypto attack in history. According to cybersecurity firm Mandiant, that breach was caused by malware on a developer’s computer, which gave attackers unauthorized access through stolen AWS tokens.

Other major incidents include:

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  In April 2025, a senior individual was scammed into losing $330 million in BTC via a social engineering scheme. The funds were laundered through 300 different wallets, though only $7 million was frozen immediately.

• The ByBit case and other well-known hacks now pale in comparison to the scale of LuBian’s loss.

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What This Means for Crypto Security

The LuBian hack serves as a harsh reminder for everyone in the crypto ecosystem:

• Always use strong, verifiable random number generators for private key creation.

• Never rely on outdated algorithms that may be brute-forced.

• Adopt multi-layered security strategies including hardware wallets, air-gapped systems, and ongoing audits.

As the value of stolen funds continues to rise, so does the sophistication of attacks. This incident highlights that even industry giants can fall victim when cryptographic foundations are weak.