User:Bernardolferreira/sandbox

= Searchable Encryption = Searchable Encryption is a family of cryptosystems specifically designed for securing the privacy of outsourced databases, while maintaining the ability to search over their encrypted contents. Generally speaking, there are two kinds of Searchable Encryption Schemes: Searchable Public-Key Encryption (SPE, also known as Public-Key Encryption with Keyword Search (PEKS) or Deterministic encryption ); and Searchable Symmetric Encryption (SSE).

Searchable Public-Key Encryption (SPE)
The concept of Searchable Public-Key Encryption (SPE) or Public-key Encryption with Keyword Search (PEKS) was first introduced by Boneh et al. in 2004. Basically, in such a cryptosystem multiple entities (Data Generators) can store/send data in a user's behalf using her public key. Furthermore, other entities (Data Searchers) can be given trapdoors of specific keywords by the user, through a function of her private key, which can be used to test if an encrypted document contains those keywords. Finally, the user, which is the only entity with access to the private key, can decrypt the encrypted data that was generated by the Generators and searched by the Searchers. A practical application of these schemes, envisioned by Boneh et al., would be an intelligent, privacy-preserving email router. In this scenario, Alice has an outsourced email service account, provided by Charlie, which she accesses through different devices. Depending on specific keywords, Alice may wish that some emails be routed to one device and others to another device. However, both the contents of emails and keywords should be encrypted as Alice doesn't trust the email service provider, Charlie. As such, Alice sends some encrypted keywords to Charlie, under the form of trapdoors and built through a function of her private key, which Charlie will use to route Alice's emails without accessing their contents. Furthermore, when Bob wants to send Alice an email, it sends it encrypted with Alice's public key to Charlie's servers, which then proceeds with the privacy preserving routing. Finally, Alice just has to decrypt Bob's emails with her private key on her device of choice.