International Association
for Cryptologic Research

We propose a new cryptographic primitive called verifiably encrypted threshold key derivation (VETKD) that extends identity-based encryption with a decentralized way of deriving decryption keys. We show how VETKD can be leveraged on modern blockchains to build scalable decentralized applications (or dapps) for a variety of purposes, including preventing front-running attacks on decentralized finance (DeFi) platforms, end-to-end encryption for decentralized messaging and social networks (SocialFi), cross-chain bridges, as well as advanced cryptographic primitives such as witness encryption and one-time programs that previously could only be built from secure hardware or using a trusted third party. And all of that by secret-sharing just a single secret key...