> For the complete documentation index, see [llms.txt](https://pegasys.gitbook.io/pegasys-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://pegasys.gitbook.io/pegasys-docs/technical-details/pegasys-hub.md).

# PegaSys Hub

The PegaSys Hub is the term used to describe the singleton lightning node that is controlled by the network’s Schnorr\[4] key. Each PegaSys node holds a shard of the network key, and all (Bitcoin and Lightning) transactions done by the system must go through a threshold signature scheme\[5] (TSS). The signature threshold is set to 2f + 1, where f is the number of failures the system can tolerate, to ensure a majority honest approval for every transaction. Once enough nodes have verified and signed the transaction, a single node broadcasts the transaction to the intended recipient. Once signed, each transaction also needs to be added to PegaSys’s internal ledger for the bookkeeping of user funds.