The seizure by US authorities of US$13.4 billion worth of bitcoin from an alleged Cambodian criminal has raised questions over the safety of the digital assets and prompted frantic speculation in the crypto community over how the feat was accomplished. Weak private keys and insider theft could have made it possible for US law-enforcement agencies to track down the bitcoin privately held by Chen Zhi, who is accused of running a massive “pig butchering” operation in Cambodia, according to experts....