The US National Security Agency monitors actions in the bitcoin blovkchain in order to identify users of crypto currency. This is reported by The Intercept, which received a set of documents from a former employee of the NSA Edward Snowden, according to which the monitoring of BTC transactions is one of the main priorities of the agency.
They also say that the work of the NSA in this direction may not be limited to analyzing the blockchain and include the detection of crypto users.
The published document indicates that the NSA has become more likely to collect passwords of bitcoin users, data about their activity on the Internet and the identity of their devices.
According to the report, the NSA monitors bitcoin users from 2013 through a program code-named OAKSTAR, as well as the MONKEYROCKET program, which is the OAKSTAR project. The data collected over the years can allow the NSA to accurately identify participants in crypto-currency transactions.
For information on bitcoin users, the NSA can use XKeyScore, a powerful system for monitoring Internet activity, which became known in 2013, when Snowden revealed information about the surveillance of the NSA.
The document says that the information collected by the Agency is stored in the file "Provider user full.csv", and details of identification of time stamps and Internet addresses of users for the purpose of determining their location are given.