[troquerre]

A miner wouldn’t be able to do that. Only the private key owner of Google could do that. At most a miner could do a double spend attack (would cost a lot more than $2000), but that wouldn’t change the DNS record for Google.

[EGreg]

The question is how do you know that the owner of the private key is the “owner of GOOGLE”. That’s what CA’s solve. Blockchain doesn’t solve this problem.