According to Planet Money, an in person block chain is used in at least one prison. http://www.npr.org/sections/money/2017/02/10/514577243/episode-753-blockchai

According to Planet Money, an in person block chain is used in at least one prison. http://www.npr.org/sections/money/2017/02/10/514577243/episode-753-blockchain-gang http://www.npr.org/sections/money/2017/02/10/514577243/episo...