Washoe County, Reno, in the State of Nevada, uses Ethereum blockchain to provide immutable digital record of wedding certificates. The service allows certified copies of marriage certificates to be emailed. It requires no special technology besides the ability to view a plain PDF.
The county uses the services of a company called TitanSeal. At https://www.washoecounty.us… you may find a complete explanation of the service.
For more information Francesca Giannoni-Crystal and Federica Romanelli.