There are things like cryptdb: https://m-cacm.acm.org/magazines/2012/9/154574-cryptdb-processing-queries-on-an-encrypted-database/fulltext https://m-cacm.acm.o

There are things like cryptdb: https://m-cacm.acm.org/magazines/2012/9/154574-cryptdb-processing-queries-on-an-encrypted-database/fulltext https://m-cacm.acm.org/magazines/2012/9/154574-cryptdb-proce... Update: It's been a while since I've looked into encrypted databases. They do a reasonable job, but they are limited in various ways. Private Information Retrieval is also interesting. https://en.m.wikipedia.org/wiki/Private_information_retrieval https://en.m.wikipedia.org/wiki/Private_information_retrieva...