Why Dogecoin's mining security has run through Litecoin since 2014 @dogecoin descends from @litecoin's codebase and uses the same Scrypt mining algorithm as litecoin:native. That overlap became a security concern in 2014, as miners swung between the two chains chasing rewards. The fix was merged mining. Since block 371,337 in September 2014, miners can submit one proof of work to both networks and collect rewards on each. The upgrade was mandatory, and nodes that skipped it could no longer send or receive dogecoin:native. The chains still keep separate ledgers and rules; only the mining work is shared.