# Ark Authors - Ark Deep Dive (Highlights) ![rw-book-cover|256](https://readwise-assets.s3.amazonaws.com/static/images/article0.00998d930354.png) ## Highlights - Service providers, on the other hand, are always-on servers that provide liquidity to the protocol. ^622609355 - Ark requires [BIP-118](https://github.com/bitcoin/bips/blob/master/bip-0118.mediawiki) or [BIP-119](https://github.com/bitcoin/bips/blob/master/bip-0119.mediawiki) covenant primitives to constrain transaction outputs of a spending transaction to make the receiving on the protocol non-interactive. ^622609356 - To improve the anonymity set of the coin ownership, *vTXOs* values are restricted to a set of sats ranging from one sat to a million sats. ^622609357 Discrete values