The term cloud computing is used in abundance nowadays: films are streamed from the cloud, documents are remotely stored and computations can be delegated to the cloud. When transmitting data, we take great care in making sure that our data is properly encrypted. It would be rather inconvenient if someone would obtain our credit card information while paying on the internet or our password would get leaked when logging into our favorite homepage. However, we usually do not think much about the computer at the other end of the connection. In other words, we assume that the only potentially malicious part of the communication protocol happens between the computers. What if you had to perform computations on sensitive data on a remote server, but you wanted to prevent the server from knowing about the computation? This is something that one can achieve with [[Quantum Computer| quantum computers]], and the aim of *blind quantum computation* protocols. These protocols enable a classical client to instruct a quantum computer to perform computations without being aware of the actual computation. Unfortunately, [[Complexity Theory|complexity theory]] suggests that achieving this ideal scenario is extremely difficult. The reason is that fully hiding the computation from the quantum computer would require the client to do almost as much work as the quantum computer itself—defeating the purpose of delegating the task in the first place. However, by giving the client limited quantum abilities or allowing communication with multiple, separate quantum devices, blind quantum computation can still be achieved in a practical way. These settings usually rely on [[Quantum Network|quantum networks]] to transfer quantum information between the client and the server. Additionally, some blind quantum computation protocols can verify the quantum computation by interspersing the actual computation with test computations which can be checked classically. >[!read]- Further Reading >- [[Quantum Computer]] >- [[Quantum Communication]] >[!ref]- References > - J. F. Fitzsimons, Private quantum computation: an introduction to blind quantum computing and related protocols, Npj Quantum Inf **3**, 1 (2017).