Private multi-signature protocol Nucleo has raised a $4 million seed round led by Bain Capital Crypto and 6th Man Ventures, The Block reported. Nucleo aims to create a private multi-signature solution for organizations to conduct transactions on the Ethereum blockchain through zero-knowledge cryptography. In August, Nucleo started internal testing on Aztec Network, a privacy and expansion solution based on ZK Rollup. Using multi-signature and zero-knowledge cryptography technology, Nucleo allows users to conduct private transactions, private DeFi, private fundraising and other operations by viewing keys .