> For the complete documentation index, see [llms.txt](https://docs.hyphen.at/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hyphen.at/concepts/hyphen-multi-sig-account/server-key.md). # Server Key Since Hyphen's multi-sig always requires at least two keys ***(2 of N)***, if a user account only has a device key, there is the inconvenience of having to do 2FA every time signing a transaction. To solve this UX issue, we store a key on the Hyphen server called the ***Server Key*** (a.k.a. Custodial Key). The Server Key has an attribute called **Auto-Sign**. When signing a transaction with the Hyphen SDK, the Hyphen server always provides a Server Key signature. Therefore, from the user's perspective, they can secure two signatures— the current device key signature + server key signature— which means they can send transactions without 2FA under normal circumstances. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## 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, and the optional `goal` query parameter: ``` GET https://docs.hyphen.at/concepts/hyphen-multi-sig-account/server-key.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.