Are there any working cloud/internet solutions/products that operates on encrypted data such as systems using homomorphic encryption, secure multiparty computation, electronic voting, private information retrieval?
- IACR uses electronic, encrypted voting for their elections every year. They use Helios
- Sharemind has been used in a few applications (financial data analysis, social study)
- CipherCloud claims to do a number of things on encrypted data. There was some discussion of their work on here that was partially removed due to a DMCA request.
- Skyhigh Networks does functionality-preserving encryption of cloud apps
- CryptDB aims to build encrypted databases.
- Dyadic uses multiparty computation to protect cryptographic keys that would otherwise be compromised by a break of a single server.
- ShareMonad has been used to prototype MPC voice accumulation, regular expressions, SHA, AES, and SAT.
There is an auction system used every year by Danish sugar beet farmers to trade production rights. This system uses secure multiparty computation to keep the bids secret so that only the result of the auction is revealed. The system is described here https://eprint.iacr.org/2008/068
As far as I know it is the first real-world use of MPC.
The company Partisia spun off this project. They have done some other auction stuff, some of it with MPC.
The Estonian company Cybernetica (behind sharemind) also does some applications. In fact I think they have one of the coolest applications of MPC I have heard of: securely computing satellite collision. I am not sure if that system is in active use though. http://mpclounge.wordpress.com/2013/04/09/using-secure-computation-to-avoid-satellite-collisions/