A chameleon-hash function is a hash function that involves a trapdoor the knowledge of
which allows one to find arbitrary collisions in the domain of the function. In this paper, we …

The existence of tight reductions in cryptographic security proofs is an important question,
motivated by the theoretical search for cryptosystems whose security guarantees are truly …

Tight security is increasingly gaining importance in real-world cryptography, as it allows to
choose cryptographic parameters in a way that is supported by a security proof, without the …

We provide a generic transformation from any affine message authentication code (MAC) to
an identity-based encryption (IBE) scheme over pairing groups of prime order. If the MAC …

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

Tightly secure cryptographic schemes can be implemented with standardized parameters,
while still having a sufficiently high security level backed up by their analysis. In a recent …

Chameleon hash functions are collision resistant when only the hashing keys of the
functions are known. In particular, without the knowledge of the secret information, the …

We construct the first tightly secure signature schemes in the multi-user setting with adaptive
corruptions from lattices. In stark contrast to the previous tight constructions whose security is …

Selective opening (SO) security refers to adversaries that receive a number of ciphertexts
and, after having corrupted a subset of the senders (thus obtaining the plaintexts and the …

Generally, lattice-based cryptographic primitives offer good performance and allow for
strong security reductions. However, the most efficient current lattice-based signature …