---
id: "zkopru"
name: "ZKOPRU"
image: "zkopru.svg"
section: "archived"
projectStatus: "inactive"
category: "devtools"
tldr: "Optimistic Rollup with zk-SNARKs for private Ethereum transactions."
tags:
  keywords: ["anonymity/privacy", "private transactions"]
links:
  website: "https://zkopru.network/"
  github: "https://github.com/zkopru-network"
---

### Overview

ZkOPRU (Zero-Knowledge Optimistic Private Rollup) is a Layer 2 scaling solution for Ethereum designed to enable private transactions while maintaining scalability and compatibility with
the Ethereum ecosystem. It combines zero-knowledge proofs (specifically zk-SNARKs) with optimistic rollup technology to provide a privacy-focused framework for transferring ETH,
ERC-20 tokens, and ERC-721 NFTs. The project aims to address Ethereum's limitations in transaction privacy and cost by moving computation off-chain while ensuring security through
cryptographic proofs and Ethereum's mainnet as the settlement layer.

### History

ZkOPRU was developed as an open-source initiative, with significant contributions from developers like Barry Whitehat and Wanseob Lim. Its first testnet was announced in July 2020,
marking a milestone in bringing privacy to Ethereum's public blockchain. The system operates by batching transactions into a rollup, where zk-SNARKs shield sensitive details—such
as sender, recipient, and amount—while optimistic rollups assume transaction validity unless challenged, reducing the need for immediate on-chain verification. This hybrid approach
allows ZkOPRU to offer low-cost, private transactions with the ability to scale, supporting use cases like confidential payments and private NFT transfers.

The project emerged from earlier efforts like ZK Rollup but distinguishes itself with its optimistic mechanism, which avoids the high computational cost of generating zero-knowledge
proofs for every transaction on-chain. Instead, it uses a challenge period during which invalid transactions can be disputed, balancing efficiency and security. ZkOPRU also includes
a coordinator system to manage transaction batching, though it aims to minimize trust assumptions over time.

### Features

- **Privacy**: Transactions are shielded using zk-SNARKs, ensuring confidentiality on a public ledger.
- **Scalability**: Optimistic rollups bundle hundreds of transactions into a single proof, lowering gas fees and increasing throughput.
- **Compatibility**: Supports Ethereum-native assets (ETH, ERC-20, ERC-721), making it versatile for existing applications.
- **Decentralization**: Relies on Ethereum for final settlement, inheriting its security while offloading computation.

### Impact

As of March 26, 2025, ZkOPRU remains a notable experiment in Ethereum's privacy and scaling landscape, though its development has been somewhat overshadowed by other Layer 2 solutions
like zkSync and Arbitrum. Its GitHub repository (under the zkWizard organization) and initial testnet documentation provide insight into its technical design, which includes a
UTXO-based model for transaction tracking and a focus on user accessibility via wallet integration. While it hasn't achieved widespread adoption, ZkOPRU's influence is seen in the
broader trend of combining zero-knowledge cryptography with rollup technology, paving the way for projects like Aztec and Polygon Nightfall.

In summary, ZkOPRU is a pioneering effort to bring privacy to Ethereum's Layer 2 ecosystem, leveraging zk-SNARKs and optimistic rollups to offer a scalable, confidential transaction
layer as of its last significant updates around 2020-2021.
