Over the last two years, though, RPKI has gained some real momentum, and is now in use by ISPs like AT&T, Telia, NTT, and Cogent. On Monday, the European network service provider RETN announced that it has implemented RPKI. And in November, Google completed RPKI registration for more than 99 percent of its routes.
Update: Microsoft also announced last week it's signed all of its BGP routes.