# EO Chain ### Expansion Chain Expansion chains are blockchains that rely on a primary chain for security. They can be implemented using EigenLayer, Avalanche subnets and Polygon 2.0. Compared to a new blockchain, an expansion chain is easier to bootstrap, as it can rely on the security of the primary chain. Nodes can be required to stake on the primary chain, using its tokens as collateral to ensure their good behavior. Due to the established security of the primary chain, the value of its tokens is more stable, and the nodes are more likely to remain correct. {% content-ref url="../understand-eo-1/security/aegis-validator-set-configuration" %} [aegis-validator-set-configuration](https://docs.eo.app/docs/understand-eo-1/security/aegis-validator-set-configuration) {% endcontent-ref %} ### EO-Chain as an Expansion Chain In creating the architecture for a fully decentralized blockchain oracle network, EO aims to build a system inherently aware of its operational dynamics, ensuring comprehensive tracking of participant actions and outcomes within a transparent and immutable framework. Ideally, the best blockchain oracle infrastructure would be Ethereum itself, but the high costs and latency of on-chain processes make this infeasible. To address this, we established the "EO-Chain," a dedicated Proof-of-Stake (PoS) blockchain operated by Eigen operators—Ethereum validators restaking their ETH to secure the network. The EO-chain offloads computation from the main blockchain, reducing costs and latency while maintaining decentralized incentives for blockchain oracle operators. This setup allows all calculations to occur on-chain, ensuring transparency and security. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.eo.app/docs/concepts/eo-chain.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.