Deterministic and Efficiently Searchable Encryption

• Published in: Advances in Cryptology Vol. 4622; pp. 535 - 552
• Main Authors: Bellare, Mihir, Boldyreva, Alexandra, O’Neill, Adam
• Format: Book Chapter
• Language: English
• Published: Germany Springer Berlin / Heidelberg 2007; Springer Berlin Heidelberg
• Series: Lecture Notes in Computer Science
• Subjects: Encrypt Data; Encryption Algorithm; Encryption Scheme; Random Oracle; Range Query
• ISBN: 3540741429; 9783540741428
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/978-3-540-74143-5_30

We present as-strong-as-possible definitions of privacy, and constructions achieving them, for public-key encryption schemes where the encryption algorithm is deterministic. We obtain as a consequence database encryption methods that permit fast (i.e. sub-linear, and in fact logarithmic, time) search while provably providing privacy that is as strong as possible subject to this fast search constraint. One of our constructs, called RSA-DOAEP, has the added feature of being length preserving, so that it is the first example of a public-key cipher. We generalize this to obtain a notion of efficiently-searchable encryption schemes which permit more flexible privacy to search-time trade-offs via a technique called bucketization. Our results answer much-asked questions in the database community and provide foundations for work done there.