The US sentenced a blockchain expert to over five years in prison after he conspired to help North Korea evade sanctions using cryptocurrency.

Virgil Griffith, a doctorate holder from the California Institute of Technology, pleaded guilty; his sentencing included a $100,000 fine.  The 39-year-old has previously worked at Ethereum and visited North Korea in April 2019.

He spoke at the Pyongyang Blockchain and Cryptocurrency Conference, even though the US State Department had denied him permission to go. In September 2021, Griffith pleaded guilty to conspiring to violate the US International Emergency Economic Powers Act. 

Prosecutors said Griffith was aware that the information he presented in North Korea could be used to evade sanctions that Washington had put on North Korea regarding its nuclear weapons. 

"The most important feature of blockchains is that they are open. And the DPRK [Democratic People's Republic of Korea] can't be kept out no matter what the USA or the UN says," Griffith said during his presentation in North Korea, according to prosecutors.

The US Department of Justice said Griffith had undermined these sanctions and "jeopardized the national security of the United States."