# XCHandles From a technical standpoint, XCHandles is, at its core, a `HashMap` that transforms the hash of a handle (i.e., `sha256tree` of the handle string) to a singleton launcher id. Entries usually point to a name NFT launcher id, which contains details such as receiver address (resolved as the owner of the NFT), as well as other info in their metadata (e.g., display name and image). Each entry can only be updated or transferred by its owner. Entries also have expiration dates - after registration, anyone may extend the validity of a handle. After the handle expires, it enters an auction process handled by another puzzle (set to the 'exponential premium' puzzle at launch). Before proceeding, it's highly recommended that you familiarize yourself with the primitives in the [CATalog docs](https://docs.catalog.cat/technical-manual/slots), as XCHandles uses them in more complex ways. Note that the XCHandles registry also includes a [delegated state action](https://docs.catalog.cat/technical-manual/other-useful-concepts#the-delegated-state-action). Generally, announcements and messages from the main registry are sent using a one-byte prefix followed by a hash of the actual message contents. To prevent collisions, the prefixes and message structures are defined in a single file ([here](https://github.com/Yakuhito/slot-machine-chia-wallet-sdk/blob/main/crates/chia-sdk-driver/src/primitives/action_layer/xchandles_registry_prefix.rs)). ### Slots Handle slots contain data about registered handles and use a nonce of **1**. Slots tracking initiated updates use a nonce of **2**. More information about the data held in these slots can be found under [The Register Action](/techincal-manual/xchandles/the-register-action.md) and [The Initiate Update Action](/techincal-manual/xchandles/the-initiate-update-action.md). *Written by* [*yakuhito*](https://x.com/yakuhito) *from* [*FireAcademy.io*](https://fireacademy.io/) *on Feb 15th, 2025.* --- # 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.xchandles.com/techincal-manual/xchandles.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.