NuCypher (NU) is a decentralized system that seeks to provide encryption, access control, and key management services. It is designed to facilitate end-to-end encrypted data sharing on public blockchains and decentralized storage solutions. The native tokens of the NuCypher network, NU, are used to incentivize network participants for performing key management services and accessing delegation/revocation operations. NU tokens are also used to operate a NuCypher worker node and participate in the NuCypher DAO, a protocol that controls network parameters and smart contract upgrades.

NuCypher operates using proxy re-encryption (PRE) technology, which allows users to share private data between multiple participants in public consensus networks. This technology aims to enhance the security of NuCypher, which is based on public-key encryption. The network is protected against malicious activities and can automatically reduce a suspected user’s compensation. The cryptographic libraries of NuCypher include pyUmbral, the reference implementation of the Umbral threshold proxy re-encryption scheme; NuBLS, a threshold BLS signature library; and rust-umbral, a Rust implementation of Umbral with bindings to JavaScript and Python.

NuCypher is designed to serve as a privacy layer for other blockchains. It provides a privacy infrastructure for the decentralized web with proxy re-encryption (PRE), threshold signatures (TSS), distributed key generation (DKG), and other threshold cryptography. Users can conditionally grant and revoke access to data with multiple users at a time using the NuCypher network. Its encryption service aims to provide high-level security for sensitive data transfer, combining this with the trustless and censorship-resistant nature of conventional public blockchains.

NuCypher was co-founded by Mikhail Egorov, the founder of Curve, and MacLane Wilkison. The white paper for NuCypher was first published in June 2017, but the testnet did not launch until November 2018. Both Egorov and MacLane participated in the U.S. startup accelerator Y Combinator in the summer of 2016. The private testnet of NuCypher launched in 2018, with participation from major infrastructure providers. The public testnet began in October 2019, and the mainnet launched in October 2020, following the allocation of NU tokens to nodes.