This reduces to the same problem of trusting a single third party with your search queries. If I understand correctly, a corrupt or compromised GoogleSharing pr

This reduces to the same problem of trusting a single third party with your search queries. If I understand correctly, a corrupt or compromised GoogleSharing proxy could leak your searches. This is not a hypothetical threat. There are already false anonymous proxies deployed and being monitored. A mix net can address that issue, but then we're just talking about something like Tor.