# Reducing Costs through Trust Assumptions At the core of the Arbitrum protocol lies the necessity for all Arbitrum nodes, including validators who verify the chain's correctness and stake on accurate results, to have access to the data of every Layer 2 (L2) transaction within the Arbitrum chain's inbox. Traditionally, an Arbitrum rollup ensures data access by posting data on Layer 1 (L1) Ethereum as calldata, a process incurring substantial Ethereum gas fees, which is the primary cost component in Arbitrum. AnyTrust, however, introduces a paradigm shift by entrusting an external entity known as the Data Availability Committee (the "Committee") with the storage and on-demand provision of data. The Committee consists of N members, with a trust assumption that at least two members are honest. This trust assumption guarantees data availability for the proper functioning of the rollup protocol, as even if N-1 Committee members promise to provide access to certain data, at least one of the promising entities must be honest, ensuring data availability up to the specified expiration time. --- # 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://xai-foundation.gitbook.io/xai-network/en/about-xai/xai-protocol/anytrust-revolutionizing-blockchain-infrastructure/reducing-costs-through-trust-assumptions.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.