Learn More
In the public key cryptosystems, revocation functionality is required when a secret key is corrupted by hacking or the period of a contract expires. In the public key infrastructure setting, numerous solutions have been proposed, and in the Identity Based Encryption (IBE) setting, a recent series of papers proposed revocable IBE schemes. Delegation of key(More)
Efficient and privacy-preserving constructions for search functionality on encrypted data is important issues for data outsourcing, and data retrieval, etc. Fully secure anonymous Hierarchical ID-Based Encryption (HIBE) schemes is useful primitives that can be applicable to searchable encryptions [4], such as ID-based searchable encryption, temporary(More)
In ACM CCS 2008, Boldyreva et al. proposed an elegant way of achieving an Identity-based Encryp-tion (IBE) with efficient revocation, which we call revocable IBE (RIBE). One of the significant benefit of their construction is scalability, where the overhead of the trusted authority is logarithmically increased in the number of users, whereas that in the(More)
At Eurocrypt 2010, Freeman proposed a transformation from pairing-based schemes in composite-order bilinear groups to equivalent ones in prime-order bilinear groups. His transformation can be applied to pairing-based cryptosystems exploiting only one of two properties of composite-order bilinear groups: cancelling and projecting. At Asiacrypt 2010,(More)
We put forward new techniques for designing signature schemes. As a result, we present practical signature schemes based on the CDH, the RSA, and the SIS assumptions. Our schemes compare favorably with existing schemes based on these assumptions. Our core idea is the use of tag-based signatures. Concretely, each signatures contains a tag which is uniformly(More)
Secure computation of the set intersection functionality allows n parties to find the intersection between their datasets without revealing anything else about them. An efficient protocol for such task could have multiple potential applications, in commerce, health-care, and security. However, all currently known secure set intersection protocols for n > 2(More)
At Crypto 2013, Coron, Lepoint, and Tibouchi (CLT) proposed a practical Graded Encoding Scheme (GES) over the integers, which has very similar cryptographic features to ideal multilinear maps. In fact, the scheme of Coron et al. is the second proposal of a secure GES, and has advantages over the first scheme of Garg, Gentry, and Halevi (GGH). For example,(More)
We introduce the idea of associating a set of elements with a rational function represented using a reversed Laurent series. Using this representation, we propose private set-union protocols in the multi-party setting, assuming an honest majority. Our protocols are the first efficient protocol for private set union with constant round complexity (in both(More)