1. I guess nothing is certain - but even if they are a complete hoax they still can't correlate searches with my other data (mobile, mail, documents, http header data from javascript api calls on basically every site I visit, ....). This correlation is something other search engines explicitly state that they will do.

2. You don't know that.

I wonder if it's possible to make a search engine that people can verify is not spying on them. One where the source is truly open source. Not just on github, but where anyone who wants to can ssh into the server and have full read-only access to the whole system to verify that the code they see is really what's running. Sure, there'd be some security things to work out to make it balance how easy it'd be to hack it, but maybe it's doable.

See also https://en.wikipedia.org/wiki/Homomorphic_encryption

If I can SSH in and have full read only access on the server what's to stop me seeing what other users are doing, thus ending user privacy?

I am really surprised people on HN do not know about YaCy [1]. It's p2p opensource and free search engine. So it is verifiable.

[1]. yacy.net

> 1. You don't know that.

Have they been audited? That could help.

absolutely true, but basically it just means, we need to make it easy to build search engine infrastructure