From MIT News:
Generally, users have no idea which data items their apps are collecting, where they’re stored, and whether they’re stored securely. Researchers at MIT and Harvard University hope to change that, with an application they’re calling Sieve.
With Sieve, a Web user would store all of his or her personal data, in encrypted form, on the cloud. Any app that wanted to use specific data items would send a request to the user and receive a secret key that decrypted only those items. If the user wanted to revoke the app’s access, Sieve would re-encrypt the data with a new key.
“This is a rethinking of the Web infrastructure,” says Frank Wang, a PhD student in electrical engineering and computer science and one of the system’s designers. “Maybe it’s better that one person manages all their data. There’s one type of security and not 10 types of security. We’re trying to present an alternative model that would be beneficial to both users and applications.”
Sieve required the researchers to develop practical versions of two cutting-edge cryptographic techniques called attribute-based encryption and key homomorphism.With attribute-based encryption, data items in a file are assigned different labels, or “attributes.” After encryption, secret keys can be generated that unlock only particular combinations of attributes: name and zip code but not street name, for instance, or zip code and date of birth but not name.
Read the Complete Article
See Also: “Sieve: Cryptographically Enforced Access Control for User Data in Untrusted Clouds” (16 pages; PDF)
Full text of the conference paper discussed in the article.