by 8144225309

SuperScalar puts many self-custodial Lightning clients behind a single on-chain UTXO, with no soft fork and no trust in the coordinating LSP. It is @ZmnSCPxj’s design (SuperScalar with pseudo-Spilman leaves, t/1242); this post reports a working implementation.

Everything below ran on regtest or signet. There has been no external audit, and mainnet is deliberately behind an explicit --i-accept-the-risk flag.

Code (C, MIT, at v0.2.0): github.com/8144225309/SuperScalar. Four binaries: superscalar_lsp, superscalar_client, superscalar_watchtower, superscalar_bridge.

How a channel factory is builtHow a channel factory is built

A channel factory is one P2TR funding UTXO whose internal key is a MuSig2 aggregate of the LSP and up to 127 clients (128 signers including the LSP). Every output at every layer can be spent only by the aggregate signature of everyone beneath it, so no subset of participants, the LSP included, can move funds that are not theirs. Even the factory’s expiry favors the clients rather than the LSP (the distribution transaction, below). There is no one-honest-member assumption anywhere: from the moment a client is onboarded to the moment it exits, its safety rests on its own key and on consensus-enforced timelocks, not on the honesty of the LSP or of any co-client. The mechanisms of t/1242, walking down the tree:

The smallest canonical shape, for orientation (8 clients, interior arity 2, k=2 pseudo-Spilman sub-factories per leaf, ZmnSCPxj’s canonical t/1242 shape; the shipping default is one client per leaf, k=1; L = the LSP):

funding UTXO  =  MuSig2(A..H, LSP)

|
kickoff_root     (n-of-n, no timelock)
|
state_root       (DW, decrementing nSeq)
|
+-- leaf_1  (A-D)
|    +-- A&B&L or L&CSV -> A-L, B-L
|    +-- C&D&L or L&CSV -> C-L, D-L
|    +-- A&B&C&D&L or L&CSV -> L-stock
+-- leaf_2  (E-H)
      +-- E&F&L or L&CSV -> E-L, F-L
      +-- G&H&L or L&CSV -> G-L, H-L
      +-- E&F&G&H&L or L&CSV -> L-stock

...read more at delvingbitcoin.org