TLDR
- Arkham Intelligence uncovered a 2020 Bitcoin theft from Chinese mining pool LuBian worth $3.5 billion at the time
- 127,426 BTC was stolen on December 28, 2020, making it the largest crypto heist in history by value
- The stolen Bitcoin is now worth $14.5 billion due to price appreciation since 2020
- LuBian sent over 1,500 messages to the hacker’s wallet addresses requesting return of funds
- The theft went unreported by both parties and remained undetected for nearly five years
Blockchain analytics firm Arkham Intelligence revealed the largest cryptocurrency theft in history went undetected for nearly five years. The firm discovered that Chinese mining pool LuBian lost 127,426 Bitcoin worth $3.5 billion in December 2020.
LuBian was one of the world’s largest mining pools in 2020, controlling almost 6% of the Bitcoin network’s total hash-rate as of May 2020.
They appear to have been first hacked on December 28th, 2020 for over 90% of their BTC. Subsequently, on December 29th, around $6M of… pic.twitter.com/X7wLknUCI5
— Arkham (@arkham) August 2, 2025
The theft occurred on December 28, 2020, when hackers drained over 90% of LuBian’s Bitcoin holdings. LuBian was one of the world’s largest mining pools at the time, controlling nearly 6% of Bitcoin’s total hash rate.
Two days after the initial theft, another attack targeted LuBian addresses on the Bitcoin Omni layer. This second breach involved approximately $6 million worth of Bitcoin and USDT.
LuBian moved its remaining 11,886 Bitcoin into recovery wallets by December 31, 2020. The mining pool appears to have kept the massive theft secret from the public.
Silent Pleas for Recovery
Arkham’s analysis revealed LuBian sent over 1,500 messages to the hacker’s wallet addresses. The mining pool used OP_RETURN transactions to embed data directly into the Bitcoin blockchain.
These messages cost LuBian approximately 1.4 Bitcoin in transaction fees. The messages urged the thief to return the stolen funds.
The presence of these messages suggests they came from the legitimate wallet owner. Neither LuBian nor the suspected hacker has publicly acknowledged the breach.
Security Vulnerability Exposed
Arkham believes the theft resulted from flawed private key generation. The mining pool may have used an algorithm susceptible to brute-force attacks.
This vulnerability exposed security weaknesses in early mining infrastructure. The attack highlights the importance of robust random number generators for creating private keys.
The stolen Bitcoin has remained largely dormant since the theft. The last major movement was a wallet consolidation in July 2024.
Record-Breaking Theft Value
The stolen funds are now worth approximately $14.5 billion at current Bitcoin prices. This makes the wallet associated with the LuBian hacker the 13th largest Bitcoin holder tracked by Arkham.
The theft surpasses other major cryptocurrency breaches by nominal value at the time of loss. Previous record holders included the Mt. Gox and Bitfinex hacks.
Both the hacker and LuBian are believed to still control their respective Bitcoin balances. Arkham has published wallet trackers for both parties but has not disclosed additional identity information.
