For the past several years, bitcoin has been a way to keep financial transactions discreet. It is incredibly difficult to trace, because it does not pass through a financial institution, and it is secure because it requires a two factor identification that uses a public key and a PIN combined with a mathematical function to allow a transaction.
This has made it easy for ransomware hackers to extort money by decrypting the victim's files. These types of attackers typically demand payment in bitcoin to keep from being traced. But for the past two years, Chainalysis, a bitcoin-tracing tech startup, has been selling its product to law enforcement agencies around the world.