## Nebra introduction
NEBRA is a research & development organization dedicated to advancing the use of zero-knowledge proofs to enable a more private and scalable blockchain future.

Nebra focuses on research and development of technologies and infrastructure aimed at the mass adoption of ZKPs.

A key initiative for NEBRA is enhancing Ethereum's proof settlement capabilities in a way that is both trustless and resistant to censorship by developing Universal Proof Aggregation(UPA). Nebra's UPA is designed to aggregate proofs from various circuits, systems, and parties to address one of the primary barriers to a zero-knowledge future: the high cost of on-chain proof verification. The costs to verify different ZKPs on Ethereum can range significantly, making it expensive for many potential applications and users.

NEBRA’s solution involves using recursive SNARKs to prove multiple ZKPs off-chain and verify a single aggregated proof on-chain, drastically reducing costs and improving efficiency. This approach aims to make ZKP verification more affordable and accessible, broadening its application and adoption.

## Moving application at scale onchain

Currently, many applications are creating on-chain experiences for their users. Notably, major exchanges are developing their own rollups to leverage more value from their existing user flows. For instance:

- OKX's [X Layer](https://www.okx.com/xlayer): using Polygon CDK + AggLayer
- Coinbase's [Base](https://www.base.org/): using Optimism + Superchain

Centralized exchanges have significant opportunities to develop a robust on-chain economy leveraging their existing user base and convenient fiat on- and off-ramps.

## Why build with NEBRA OS?

NEBRA OS (OpenStack) is a **native** interoperability solution for Rollups, it enables **secure**, **fast**, **composable** cross rollup transactions.

At it's core, NEBRA OS uses NEBRA's universal proof aggregation protocol (UPA) technology (the fastest, only in production universal proof aggregation engine) to aggregate the validity proofs of different rollups and brings trustless composability of cross-rollup transactions.

With NEBRA OS, Hashkey could implement a zk rollup that integrates seamlessly with any application seeking to reduce costs through aggregated zero-knowledge proofs (zkp).


- Docs of NEBRA UPA: https://docs.nebra.one/
- Slides of NEBRA OS (previously named shared settlement layer): [slides](https://docs.google.com/presentation/d/158Eh9B73X3M3siEcka__TxVokkD_4RFK7wlVn39BuCo/edit?usp=sharing)

## NEBRA's OpenStack/AggLayer/OPStack

| | NEBRA OS | Polygon AggLayer| OPStack |
| -------- | -------- | --------------- | ------- |
| Technology | ZK | ZK | Op |
| Xchain Transaction Finality | 2s (* estimate) | 1 hr | 7 days |
| Interoperability | All BTC/ETH L2s | Polygon Eco | OP superchain Eco |

NEBRA UPA supported L2 VM type:
- V1: RISC Zero, Succinct SP1 (live today)
- V2: Scroll, zkSync, Polygon, Linea, Taiko (Q3 2024)

## HashKey Exchange + NEBRA OS

We would like to invite HashKey Exchange to join NEBRA OS to bring the information highway in the onchain age to HashKey Exchange users. We envision the benefit of this collaboration

- Enhance network effects through partnerships with NEBRA OS associates such as Scroll, MegaETH, RISC Zero, Succinct, and more.
- Develop a robust on-chain and off-chain economy centered around HashKey Exchange in the Asia/Pacific region.
- Collaborate on introducing advanced zero-knowledge proof technologies to Hong Kong.