While that may be true, text search over documents has certain requirements that differ from the use cases being mentioned for homomorphic encryption over the past two years (since Craig Gentry's paper on fully homomorphic encryption). Although possible over structured data that you'd find in a database, I'm not sure if there's been a clear way to apply homomorphic encryption to search. If there has been progress made in this area, I'd love to know.
In documents, keywords are scattered through the plain text and conjunctive keyword search should be possible without giving way to dictionary attacks: If I search for 'fire truck' I want a sentence 'the truck was firing up' to potentially return as a search result, but at the same time I don't want to encrypt each tokenized word ('fire', 'truck') and pattern-match the ciphertext.
Encrypted search is an active research area. One of the more interesting/cited papers I've come across on the topic is Conjunctive, Subset, and Range Queries on Encrypted Data by Boneh and Waters [1] although there are several others. Boneh also authored an earlier paper on encrypted search involving public key encryption.
In documents, keywords are scattered through the plain text and conjunctive keyword search should be possible without giving way to dictionary attacks: If I search for 'fire truck' I want a sentence 'the truck was firing up' to potentially return as a search result, but at the same time I don't want to encrypt each tokenized word ('fire', 'truck') and pattern-match the ciphertext.
Encrypted search is an active research area. One of the more interesting/cited papers I've come across on the topic is Conjunctive, Subset, and Range Queries on Encrypted Data by Boneh and Waters [1] although there are several others. Boneh also authored an earlier paper on encrypted search involving public key encryption.
[1] http://crypto.stanford.edu/~dabo/pubs/papers/search.pdf
[2] http://www.cs.berkeley.edu/~dawnsong/papers/se.pdf