Let's Encrypt is already taking steps to mitigate this. BGP hijacking is a noisy event - it should be possible to see that routes have changed recently and deny

Let's Encrypt is already taking steps to mitigate this. BGP hijacking is a noisy event - it should be possible to see that routes have changed recently and deny issuance. They can also perform challenges from multiple geos / networks, so that if there's a disagreement among routes, the challenge fails. More info: https://secure-certificates.princeton.edu/ https://secure-certificates.princeton.edu/