Written by Luca Giussani, lucagiussani@horizenlabs.io Horizen Labs developed an on-chain private voting solution which can be deployed on EVM-compatible blockchains, and is compatible with the widely adopted OpenZeppelin Governor framework. The solution migrates the well-known Helios voting protocol to on-chain, and adds linear homomorphic encryption of the votes and efficient zk-proofs to guarantee: integrity of the voting process privacy of the votes censorship resistance reasonable gas costs

Written by Markus Schofnegger, mschofnegger@horizenlabs.io Efficient hash functions play a major role in modern zero-knowledge settings. One of these hash functions, Poseidon, has found use in many of the currently used protocols, including Zcash and Mina. However, it has certain disadvantages. We identify those and present Poseidon2, a faster version of Poseidon. This work is the result of a collaboration between Horizen Labs, Ethereum Foundation, and Ponos Technology. For more details we refer to the full paper. Hash Functions in ZK Settings and Poseidon Hash functions for ZK settings are specifically designed to be efficient in use cases for computational integrity. Part of this efficiency comes from a simpler polynomial description when writing down all the functions needed to compute a single hash output. In the last couple of years, many new such hash constructions emerged, including Poseidon, Rescue, Griffin, and Anemoi. Out of these, Poseidon is arguably still the most popular one, finding its use in many well-known ZK protocols such as our ginger-lib library used in our chain network. It often also serves as the workhorse in implementations of STARK-based frameworks, one recent example being Plonky2 by Polygon.