#钱包安全事件 Traced the complete chain of the Milk Sad incident, and it indeed warrants a more detailed understanding.

The core issue is clear: between 2019 and 2020, tools like Lubian mining pools used the MT19937 pseudo-random number generator, which had a critical vulnerability, leading to the private key space being compressed from the theoretical 2^256 to a range susceptible to brute-force enumeration. At that time, wallets with weak keys held over 53,500 BTC, including 24,999 BTC transferred in a short period by whale-level accounts.

The anomaly on December 28, 2020, was a pivotal turning point—136,951 BTC was drained within hours, worth about $3.7 billion at the time. However, this transfer was not immediately classified as theft because mining pool revenues stopped and prices soared, making it difficult to distinguish whether it was a hack or a reorganization by the mining pool management. This cognitive blind spot persisted for years.

It wasn't until 2023, when the bx seed vulnerability in Libbitcoin Explorer was exposed, that reverse tracking was triggered. The Milk Sad team finally realized the truth behind the large-scale transfer in 2020—and this clue ultimately pointed to the Prince Group.

Key insight: On-chain data itself does not lie, but the time lag does. The batch of BTC remained silent from 2020 until its final consolidation in July 2024, spanning nearly five years. When the fundamental issue lies in the pseudo-random number generation process, the principle of "Not Your Keys, Not Your Coins" needs an additional prerequisite—that those keys themselves must be truly random.