One of the most important and successful tools for assessing hardness assumptions in
cryptography is the Generic Group Model (GGM). Over the past two decades, numerous …

Threshold signatures are a crucial tool for many distributed protocols. As shown by Cachin,
Kursawe, and Shoup (PODC'00), schemes with unique signatures are of particular …

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 …

We present the first fully secure Identity-Based Encryption scheme (IBE) from the standard
assumptions where the security loss depends only on the security parameter and is …

We perform a concrete security treatment of digital signature schemes obtained from
canonical identification schemes via the Fiat-Shamir transform. If the identification scheme is …

We construct the first Authenticated Key Exchange (AKE) protocol whose security does not
degrade with an increasing number of users or sessions. We describe a three-message …

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 …

This paper provides a (standard-model) notion of security for (keyed) hash functions, called
UCE, that we show enables instantiation of random oracles (ROs) in a fairly broad and …

In many cryptocurrencies, the problem of key management has become one of the most
fundamental security challenges. Typically, keys are kept in designated schemes called …

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 …