# Nadav Kohen - Generalized Bitcoin Channels (Highlights)  ## Metadata **Review**:: [readwise.io](https://readwise.io/bookreview/38569066) **Source**:: #from/readwise #from/reader **Zettel**:: #zettel/fleeting **Status**:: #x **Authors**:: [[Nadav Kohen]] **Full Title**:: Generalized Bitcoin Channels **Category**:: #articles #readwise/articles **Category Icon**:: 📰 **URL**:: [suredbits.com](https://suredbits.com/generalized-bitcoin-channels/) **Host**:: [[suredbits.com]] **Highlighted**:: [[2024-03-11]] **Created**:: [[2024-03-16]] ## Highlights - The authors introduce a novel mechanism by which we can create Lightning channels where punishment is applied to the entire channel at once rather than on a per-output basis. This means that should your counter-party try to cheat by publishing an old/revoked state, rather than claiming all channel funds by spending the revocation branch of every single channel output (2 + # of pending payments on this old state), you can instead publish a single simple transaction to claim all funds. ([View Highlight](https://read.readwise.io/read/01hrp2gcxwknta87j3h9mjhkd1)) ^691275716 - Another (arguably even nicer) property of this scheme is that this penalty mechanism does not require a symmetric state setup where both parties have their own commitment transactions, but rather both parties have a unified state with the same (single) commitment transaction! ([View Highlight](https://read.readwise.io/read/01hrp2gygb8nzz01nbvk2nvdqz)) ^691275736 - Note that while the existence of this ECDSA adaptor signature scheme means we can begin work on these unified channels and PTLCs now, Schnorr adaptor signatures are still superior to their ECDSA counterparts and when Schnorr signatures are permitted on-chain everything can be greatly simplified. ([View Highlight](https://read.readwise.io/read/01hrp2p8egf2k70f28xr31wmng)) ^691276591 - Although I think it would be foolish not to support PTLCs when implementing these channels, HTLCs are also supported by this scheme and furthermore these channels (with HTLCs on them) are fully compatible with existing HTLC Lightning channels so that it is possible for consenting individuals to experiment with “generalized channels” within the existing Lightning Network without any external parties knowing that they are routing through a new kind of channel! ([View Highlight](https://read.readwise.io/read/01hrp2qbfs7mp9zs4wvyjbgh44)) ^691276663 - In short, by using adaptor signatures to sign each other’s commitment transactions, the two parties in a channel can be sure that **if a commitment transaction is published to the blockchain, then only the publishing party’s publishing secret is revealed**. This paired with the usual per_commitment_secret being revealed to revoke old states, allows us to once again achieve our Lightning Penalty mechanism in this unified state setting. ([View Highlight](https://read.readwise.io/read/01hrp2w4deyeqb8vzew1zxsf4s)) ^691277468