> For the complete documentation index, see [llms.txt](https://doc.cess.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.cess.network/developer/cess-sdk/sdk-rust/chain.md).

# chain

This section introduces the core chain modules of the **CESS Rust SDK**.\
Each module corresponds to a specific on-chain pallet and provides both **query** and **transaction** interfaces to interact with the CESS blockchain.

These modules enable you to fetch chain state, submit transactions, and manage storage, files, and operational logic across the network.

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## Modules Overview

* [**Audit**](/developer/cess-sdk/sdk-rust/chain/audit.md)\
  Manage and query auditing operations such as proof submissions, verification snapshots, and challenge results.
* [**Balances**](https://github.com/CESSProject/doc-v2/blob/main/developer/cess-sdk/sdk-rust/chain/balances/README.md)\
  Handle balance-related queries and token transfer operations (to be expanded in later versions).
* [**File Bank**](/developer/cess-sdk/sdk-rust/chain/file_bank.md)\
  Manage buckets, files, and restoration orders. Includes APIs for uploading, deleting, and retrieving user file data.
* [**OSS (Object Storage Service)**](/developer/cess-sdk/sdk-rust/chain/oss.md)\
  Register and authorize OSS accounts to perform file-related operations on behalf of users. Provides APIs for OSS registration, updates, and permissions.
* [**Storage Handler**](/developer/cess-sdk/sdk-rust/chain/storage_handler.md)\
  Manage territories, storage space, and related financial transactions such as consignment sales, purchases, and renewals.

***

Each subdirectory includes:

* **Query APIs** - for retrieving blockchain state.
* **Transaction APIs** - for performing signed actions on-chain.

Continue to the respective module to explore available functions and usage examples.