A hidden vector encryption scheme (HVE) is a derivation of identity-based encryption, where the public key is actually a vector over a certain alphabet. The decryption key is also derived from such a vector, but this one is also allowed to have "¿" (or wildcard) entries. Decryption is possible as long as these tuples agree on every position except where a "¿" occurs.
These schemes are useful for a variety of applications: they can be used as a building block to construct attribute-based encryption schemes and sophisticated predicate encryption schemes (for e.g. range or subset queries). Another interesting application – and our main motivation – is to create searchable encryption schemes that support queries for keywords containing wildcards.
Here we construct a new HVE scheme, based on bilinear groups of prime order, which supports vectors over any alphabet. The resulting ciphertext length is equally shorter than existing schemes, depending on a trade-off. The length of the decryption key and the computational complexity of decryption are both constant, unlike existing schemes where these are both dependent on the amount of non-wildcard symbols associated to the decryption key.
Our construction hides both the plaintext and public key used for encryption. We prove security in a selective model, under the decision linear assumption.
|Title of host publication||Security and Cryptography for Networks (7th International Conference, SCN 2010, Amalfi, Italy, September 13-15, 2010. Proceedings)|
|Editors||J.A. Garay, R. De Prisco|
|Place of Publication||Berlin|
|Publication status||Published - 2010|
|Name||Lecture Notes in Computer Science|