Yes, the random padding (which is optional) is to counter-measure possible side-channel privacy attacks that could infer the domain name from the packet sizes.

Yes, the random padding (which is optional) is to counter-measure possible side-channel privacy attacks that could infer the domain name from the packet sizes. The Google documentation explains that (look for "random_padding") at https://developers.google.com/speed/public-dns/docs/dns-over-https https://developers.google.com/speed/public-dns/docs/dns-over...