{"action":"opened","issue":{"url":"https://api.github.com/repos/Electric-Coin-Company/zcash/issues/724","repository_url":"https://api.github.com/repos/Electric-Coin-Company/zcash","labels_url":"https://api.github.com/repos/Electric-Coin-Company/zcash/issues/724/labels{/name}","comments_url":"https://api.github.com/repos/Electric-Coin-Company/zcash/issues/724/comments","events_url":"https://api.github.com/repos/Electric-Coin-Company/zcash/issues/724/events","html_url":"https://github.com/Electric-Coin-Company/zcash/issues/724","id":133267144,"number":724,"title":"Make merged mining a first-class operation","user":{"login":"maaku","id":69154,"avatar_url":"https://avatars.githubusercontent.com/u/69154?v=3","gravatar_id":"","url":"https://api.github.com/users/maaku","html_url":"https://github.com/maaku","followers_url":"https://api.github.com/users/maaku/followers","following_url":"https://api.github.com/users/maaku/following{/other_user}","gists_url":"https://api.github.com/users/maaku/gists{/gist_id}","starred_url":"https://api.github.com/users/maaku/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/maaku/subscriptions","organizations_url":"https://api.github.com/users/maaku/orgs","repos_url":"https://api.github.com/users/maaku/repos","events_url":"https://api.github.com/users/maaku/events{/privacy}","received_events_url":"https://api.github.com/users/maaku/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2016-02-12T15:21:56Z","updated_at":"2016-02-12T15:21:56Z","closed_at":null,"body":"Merged mining in Bitcoin is implemented by sticking a commitment to the auxiliary block headers in the coinbase or other transaction. This is suboptimal for the chain being merged mined because aux headers of that chain require log(N) hashes where N is the number of bitcoin transactions in that block, something which is entirely meaningless to the merged mined chain.\r\n\r\nA better approach, and one Bitcoin would have used if this had been thought up in advance, is to have the block header commit to a tree of blocks, with a fixed path through that tree for each chain. A Merkle patricia trie, for example. This allows efficient merged mining with minimal impact to both chains.\r\n\r\nSince zcash is using its own proof of work, it should take advantage of this opportunity to enable proper merge mining for any future sidechains which reuse the same PoW algorithm."}}