The Frontier

Luis introduces Utreexo, a UTXO set compression method allowing lightweight nodes like phones to run on Bitcoin, overcoming the limitations of Bitcoin Core's large UTXO set. This system relies on bridge nodes creating Merkle proofs for blocks.

Utreexod 0.5 is mainnet compatible, implementing BIPs 181, 182, and 183. It incorporates SwiftSync, which reduces initial block download (IBD) bandwidth for compact state nodes (CSNs) by 75% by only requiring proofs from the last 16 blocks.

Luis explains that Utreexod is a BTCD fork implementing bridge nodes, while Floresta is a from-scratch compact state node (CSN) implementation using the Kernel consensus engine. Floresta, running on Luis's router, consumes about 200MB of RAM and minimal storage.

The Utreexo model enhances wallet privacy by removing the need for third-party APIs like Electrum, which leak user addresses and IP. Compact state nodes instead act as normal Bitcoin nodes on the network.