A former Federal Reserve employee was sentenced to 12 months’ probation and issued a $5,000 fine for installing unauthorized bitcoin software on a Fed server, a government watchdog said Monday.

Nicholas Berthaume, who worked as a network systems communications analyst at the Fed board in Washington, installed the software so he could connect to an online bitcoin network to earn bitcoins, the Fed’s inspector general said. The software was in place from about March 2012 to June 2014, according to a court document.

He was subsequently fired, the IG said, and struck a deal in October to plead guilty in U.S. District Court for the District of Columbia to one misdemeanor charge of unlawful use of government property, a charge that carried a fine of up to $100,000 and a year in jail. He received his sentence Friday.

A lawyer for Mr. Berthaume couldn’t immediately be reached for comment.

Users earn bitcoins by allowing their systems’ computing power to be part of the network that processes and verifies bitcoin transactions, the IG said. It wasn’t clear how many bitcoins Mr. Berthaume was able to earn by connecting the Fed’s servers to the network.