> For the complete documentation index, see [llms.txt](https://docs.galactica.com/galactica-developer-documentation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.galactica.com/galactica-developer-documentation/galactica-concepts/blockchain-base.md).

# Blockchain Base

Before diving into Galactica's unique features, here is an overview of the base technology it is built upon.

## Blockchain

Galactica Network is built using the [**Arbitrum Orbit SDK**](https://docs.arbitrum.io/launch-arbitrum-chain/a-gentle-introduction), a customizable Layer 2 framework for launching secure, EVM-compatible rollups with 100% on-chain validation and rapid finality. Orbit enables Galactica to implement identity-native configurations while benefiting from Arbitrum’s battle-tested scalability, governance flexibility, and ecosystem compatibility.

A detailed article on why Galactica uses the Arbitrum Orbit SDK can be found [here](https://galactica.com/news/Orbit%20connects%20chains.%20Galactica%20connects%20identity.).

## Smart contracts

Smart contracts on Galactica are based on the [Etherum Virtual Machine (EVM)](https://ethereum.org/en/developers/docs/evm/). It provides the engine for running DApps on Galactica and connecting them to features such as [Zero-Knowledge KYC](/galactica-developer-documentation/galactica-concepts/zero-knowledge-kyc.md), [Reputation](/galactica-developer-documentation/galactica-concepts/reputation.md) and [Contingent Transactions](/galactica-developer-documentation/galactica-concepts/contingent-transactions.md).

The EVM also provides the predominant [technical interface](https://ethereum.org/en/developers/docs/apis/json-rpc/) to wallets, front-end and back-end services on Galactica.

## Zero-knowledge cryptography

Zero-knowledge cryptography (ZKC) is a core enabler of Galactica's [Zero-Knowledge KYC](/galactica-developer-documentation/galactica-concepts/zero-knowledge-kyc.md) technology. It allows users to prove statements to a verifier without disclosing any more information than the statement itself.

This [repository](https://github.com/privacy-scaling-explorations/awesome-zero-knowledge-proofs) provides a great index of resources explaining ZKC.

Galactica mainly uses SNARKs developed in the [circom2](https://docs.circom.io/) framework.

## Wallet

As an EVM chain, Galactica supports most EVM wallets. For Galactica-specific features, such as zkKYC in self-custody - we provide a [Galactica Snap for Metamask](/galactica-developer-documentation/galactica-components/galactica-snap-for-metamask.md).