LWK setup with AMP2

LWK (Liquid Wallet Kit) is the Rust library for Liquid wallet operations. AMP2 uses LWK internally and venues can use it for local wallet management, PSET construction, and signing.

What LWK provides

• Wallet creation from descriptors
• Address derivation
• Transaction construction (TxBuilder)
• PSET signing (SwSigner)
• Chain scanning via Esplora
• Network configuration (testnet, mainnet)

Dependencies

Add these to your Cargo.toml:

[dependencies]
lwk_wollet = "0.7"
lwk_signer = "0.7"
lwk_common = "0.7"

Check crates.io for the latest versions.

Initialize the AMP2 client

The Amp2 client connects to an AMP2 server using your keyorigin xpub:

let keyorigin_xpub = "[b805d768/87h/1h/0h]tpubDCYEgnLyCH2okSittQNNB8JHLwPgmoEAoKcMrJDHP9dFVamsadPAFJQ77C1htgR8ksie3VksLXoryng9AUaPZSF8FwTwEv6CaHp8j2YCrds";
let amp_url = "https://amp.enterprise.blockstream.com/";

let amp2 = Amp2::new(keyorigin_xpub.to_string(), amp_url.to_string()).unwrap();

Choosing the right URL

The xpub derivation path must match the target network. Testnet uses coin type 1, mainnet uses coin type 0.

Create a software signer

If you need to sign PSETs locally (for venue initiated transfers):

use lwk_signer::SwSigner;
use lwk_common::Bip;

let signer = SwSigner::new("your twelve or twenty four mnemonic words here", false).unwrap();
let my_xpub = signer.keyorigin_xpub(&Bip::new_bip84()).unwrap();

The false parameter means testnet. Set true for mainnet.

Validate xpub/network alignment

Before registering wallets, verify that your xpub matches the target network:

// Testnet xpubs start with "tpub"
assert!(keyorigin_xpub.contains("tpub"));

// Mainnet xpubs start with "xpub"
// assert!(keyorigin_xpub.contains("xpub"));

Mismatched xpub/network combinations will produce invalid descriptors that AMP2 rejects.

Network configuration

LWK uses ElementsNetwork to configure chain parameters:

let network = amp2.elements_network(); // Returns testnet or mainnet based on URL

Use this when constructing transactions with TxBuilder to ensure correct fee handling and address encoding.

Next steps

• Wallet Registration: register a descriptor and get a WID
• Signing PSETs: build and sign transactions
• Environments: testnet vs. mainnet details