Some counties in northern Nevada began to chain blocks.Government records used to preserve digital versionsSuch as birth certificate and marriage certificate. Block chains are public databases without central institutions or decentralized ledgers. In Washoe County, about 950 couples have received digital marriage certificates since April last year. Elko County is trying to use similar technologies for birth certification. Washoe County Digital Marriage Certificate uses the Taifang block chain. Traditional marriage certificates need to wait 7 to 10 working days, while digital certificates can be sent by e-mail in less than 24 hours.