# Spaces on Bitcoin
*Spaces* are nice & memorable sovereign handles anchored in Bitcoin with minimal on-chain footprint. They are easier to share compared to an [`npub`](https://github.com/nostr-protocol/nips/blob/master/19.md#bare-keys-and-ids), and can be used to sign things just like a regular public key!
## What makes spaces special?
Spaces are anchored in Bitcoin, the most secure Proof-of-Work blockchain, and have the following properties:
* Primary spaces are community identifiers, capped at \~3600 per year, acquired through permissionless auctions on the Bitcoin blockchain.
* Each primary *Space* is a community that may issue sovereign handles off-chain known as *subspaces.*
* Spaces AND subspaces (once allocated) are permissionless and as secure as Bitcoin itself! No bridges, slashing, or any kind of optimistic security.
* The spaces protocol is designed with zk-light clients in mind making these identities verifiable on resource constrained devices.
* Subspaces do not need to trust the community operator once allocated, and they can do 100% of their transactions on-chain if they wish.
* Minimal on-chain footprint.
## Spaces vs. ENS
For full verification, you can sync the entire spaces protocol with a pruned Bitcoin full node on an old Raspberry PI. Bitcoin is the most secure Proof-of-Work blockchain today, and it's relatively lightweight compared to running an Ethereum node. The majority of ENS integrations trust centralized third-parties defeating the whole purpose of decentralized identities.
## Jump right in
.svg?alt=media&token=e9c720f0-b12b-425b-9e02-e90a60d98fbb){kind=link}