We present the first CCA-secure public-key encryption scheme based on DDH where the
security loss is independent of the number of challenge ciphertexts and the number of …

Constructing short signatures with tight security from standard assumptions is a long-
standing open problem. We present an adaptively secure, short (and stateless) signature …

We provide a structure-preserving signature (SPS) scheme with an (almost) tight security
reduction to a standard assumption. Compared to the state-of-the-art tightly secure SPS …

We construct an identity-based encryption (IBE) scheme that is tightly secure in a very strong
sense. Specifically, we consider a setting with many instances of the scheme and many …

At EUROCRYPT 2016, Gay et al. presented the first pairing-free public-key encryption (PKE)
scheme with an almost tight security reduction to a standard assumption. Their scheme is …

We propose the first identity-based encryption (IBE) scheme that is (almost) tightly secure
against chosen-ciphertext attacks. Our scheme is efficient, in the sense that its ciphertext …

We construct the first hierarchical identity-based encryption (HIBE) scheme with tight
adaptive security in the multi-challenge setting, where adversaries are allowed to ask for …

We present a new strategy for partitioning proofs, and use it to obtain new tightly secure
encryption schemes. Specifically, we provide the following two conceptual contributions: A …

Tightly secure cryptographic schemes have been extensively studied in the fields of chosen-
ciphertext secure public-key encryption, identity-based encryption, signatures and more. We …

Updatable encryption (UE) allows to periodically rotate encryption keys without the need to
decrypt and re-encrypt already encrypted data. This is achieved by means of an update …