Overview

Hush Lightwalletd is a fork of lightwalletd original from Zcash (ZEC).

It is a backend service that provides a bandwidth-efficient interface to the Hush blockchain for SilentDragonLite cli and SilentDragonLite.

Changes from upstream lightwalletd

This version of lightwalletd extends lightwalletd and:

• Adds support for HUSH
• Adds support for transparent addresses
• Adds several new RPC calls for lightclients
• Lots of perf improvements
  • Replaces SQLite with in-memory cache for Compact Blocks
  • Replace local Txstore, delegating Tx lookups to hushd
  • Remove the need for a separate ingestor

Running your own SDL lightwalletd

0. First, install Go

You will need Go >= 1.17 which you can download from the official download page or install via your OS package manager. Most OS package managers will not have such a new version, but you might get lucky.

This installation document shows how to do it on various OS's.

If you're using Ubuntu or Debian, try:

$ sudo apt install golang

1. Run a Hush node.

Either compile or build the Hush Daemon (hushd).

Next, change your HUSH3.conf file to something like the following:

rpcuser=user-CHANGETHIS
rpcpassword=pass-CHANGETHIS
rpcport=18031 # this if for HUSH, change it for other HSC's
server=1
txindex=1
addressindex=1 # required for the newest lightwalletd code
rpcworkqueue=256
rpcallowip=127.0.0.1
rpcbind=127.0.0.1

Then start hushd in your command window. You might need to run with -reindex the first time if you are enabling -addressindex option for the first time. The reindex might take a while. A fresh sync is usually the fastest way to enable -addressindex, instead of doing a reindex.

2. Compile lightwalletd

Run the build script.

make

3. Get a TLS certificate and run the Lightwalletd frontend

First, get a TLS certificate:

On Ubuntu Linux, I SUGGEST YOU DO NOT USE SNAPD and just sudo apt install certbot and then start on Step 7 of these instructions by the EFF

Next you decide how you want to setup lightwalletd - with (Option A) or without NGINX (Option B).

Option A: "Let's Encrypt" certificate using NGINX as a reverse proxy

If you running a public-facing server, the easiest way to obtain a certificate is to use a NGINX reverse proxy and get a Let's Encrypt certificate.

Create a new section for the NGINX reverse proxy:

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    
    server_name your_host.net;

    ssl_certificate /etc/letsencrypt/live/your_host.net/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/your_host.net/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
        
    location / {
        # Replace 9067 with the port of your gRPC server if using a custom port
        # Hush Smart Chains should use a different port than 9067 so it doesn't conflict with HUSH lightwalletd
        # NOTE: it's only safe to use --no-tls on lightwalletd if this is on localhost
    	grpc_pass grpc://localhost:9067;
    }
}

Then run the lightwalletd frontend with the following:

./start.sh

Note: we use the "--no-tls" option as we are using NGINX as a reverse proxy and letting it handle the TLS authentication for us instead. If you want to do TLS directly with lightwalletd with no reverse proxy, see the next section.

If you encounter an error about the lightwalletd "data directory", then set one on the command line with --data-dir (OR) create the /var/lib/lightwalletd and /var/lib/lightwalletd/db directories & chown that new db directory as the user account running lightwalletd and hushd.

Option B: "Let's Encrypt" certificate just using lightwalletd without NGINX

The other option is to configure lightwalletd to handle its own TLS authentication. Once you have a certificate that you want to use (from a certificate authority), pass the certificate to the frontend as follows:

./start-tls.sh -tls-cert /etc/letsencrypt/live/YOURWEBSITE/fullchain.pem -tls-key /etc/letsencrypt/live/YOURWEBSITE/privkey.pem

4. Point the silentdragonlite-cli to this server

You should start seeing the frontend ingest and cache the Hush blocks after ~15 seconds.

Now, connect to your server! (Substitute with your own below)

git clone https://git.hush.is/hush/silentdragonlite-cli
cd silentdragonlite-cli
cargo build --release
./target/release/silentdragonlite-cli --server https://lite.example.org

• If you have trouble compiling silentdragonlite-cli, then please refer to it's separate documentation here on how to build it and what pre-requisites need to be installed.

Lightwalletd Command-line Options

These are some of the most used command line options for lightwalletd:

CLI option	Default	What it does
--grpc-bind-addr	127.0.0.1:9067	address and port to listen on
--tls-cert	blank	the path to a TLS certificate
--tls-key	blank	the path to a TLS key file
--no-tls	false	Disable TLS, serve un-encrypted traffic
--data-dir	/var/lib/lightwalletd	Sets the lightwalletd data directory
--log-file	blank	log file to write to
--log-level	logrus.InfoLevel	log level 1 thru 7 (something from logrus)
--hush-conf-path	blank	conf file to pull RPC creds from
--cache-size	40000	number of blocks to hold in the cache

Run ./lightwalletd --help to see all options.

Developing

To create a foo.pb.go file from a foo.proto file:

protoc --go_out=paths=source_relative:. foo.proto

Or do make protobuf

Support

For support or other questions, join us on Telegram, or tweet at @HushIsPrivacy, or toot at our Mastodon or join Telegram Support.

License

GPLv3 or later

Copyright

2016-2022 The Hush Developers