Cobo co-founder Shenyu has revealed that US law enforcement agencies possess the private keys to 120,000 bitcoins. This access was not achieved through hacking or intrusion but by identifying a flaw in the randomness of private key generation. The vulnerability, which affected over 220,000 wallet addresses, was due to a flawed pseudo-random number generator (PRNG) that used a fixed offset and pattern, making the private keys more predictable.