Blockchain analytics firm Arkham Intelligence has revealed that 127,426 BTC were stolen from China‑based mining pool LuBian in December 2020, marking the largest known crypto hack ever uncovered.
Key Takeaways:
- Arkham revealed on August 3, 2025 that Chinese-Iranian mining pool LuBian lost roughly 127,426 BTC in a December 2020 breach totaling over $3.5 billion at the time and now estimated at $14.5 billion.
- Reaching over 90% of LuBian’s holdings, the theft was followed by an attempt to recover funds via 1,516 OP_RETURN messages, costing approximately 1.4 BTC in fees, but with no response from the hacker.
- Arkham believes a flawed private key generation algorithm, easily cracked by brute-force attacks, caused the exploit. Lubian quietly shut down in early 2021 and never publicly acknowledged the theft.
On August 3, 2025, Arkham Intelligence brought into light the possibly largest Bitcoin theft in history as they published a detailed on-chain investigation though an X thread. The firm found that LuBian, a Chinese‑Iranian mining pool active in mid‑2020 and contributing roughly 6% of Bitcoin’s total hash rate, was compromised in a stealth breach in late December 2020.
According to Arkham’s chain data, attackers drained over 90% of LuBian’s BTC holdings, totalling 127,426 BTC on December 28, 2020. The next day came an additional theft reaching over $6 million in BTC and USDT via a linked Omni-layer wallet. Two days later (December 31), LuBian moved its remaining 11,886 BTC to a recovery wallets in a final attempt to salvage funds.
Moreover, in an unusual on‑chain manoeuvre, LuBian sent 1,516 OP_RETURN transactions, spending ~1.4 BTC to embed messages appealing to the hacker, noting:
To the whitehat who is saving our asset, you can contact us…
But none of these messages reportedly got a response from the hacker.
Arkham believes the root cause of the breach was a flawed random‑number generator used in private key creation, enabling a brute‑force attack against wallet credentials. The intelligence platform also noted:
It appears that LuBian was using an algorithm to generate its private keys that was susceptible to brute-force attacks. This may have been the vulnerability exploited by the hackers.
Both LuBian and the hacker have remained silent and never issued public statements or warnings at the time. Arkham’s report is the first to surface the breach. The mining pool quietly disappeared in early 2021, previously chalked up to regulatory issues now understood as likely linked to this catastrophic security failure.
Price & Market Impact
As of writing (9:50AM UTC), Bitcoin (BTC) is trading at $144,443, up 0.7% over the past 24 hours according to TradingView’s latest market statistics. Arkham’s findings about the massive Bitcoin hack seemed to have no dramatic effect to the crypto market, particularly to the price of BTC. However, the revelation injects renewed scrutiny into crypto infrastructure. That $14.5 B stolen sum now represents a share equal to over 127,000 BTC, which is remarkably close to what many institutional investors hold.
What’s Next
Arkham Intelligence’s revelation of the LuBian hack underscores enduring vulnerabilities in pseudo‑institutional crypto infrastructure. With billions at stake and key generation flaws exposed, the incident amplifies the urgency for audited security protocols, robust post‑mortem disclosures, and stronger standards around cryptographic key management. This serves as a call to action to the broader crypto market that no mining pool or custodian is immune to hidden risks, and transparency is no longer optional.
Summary
Arkham Intelligence has uncovered the largest Bitcoin theft in history: 127,426 BTC ($3.5B in 2020, now worth $14.5B) stolen from China-based mining pool LuBian. The stealth breach occurred in December 2020, draining over 90% of LuBian’s holdings via a brute-force vulnerability in private key generation. LuBian attempted to contact the hacker via 1,516 OP_RETURN transactions but received no response. The pool quietly shut down in early 2021 without acknowledging the theft. While Bitcoin’s price remains unaffected, the revelation reignites urgent concerns over infrastructure transparency and wallet security.
