Blacklist Pallet

Introducing the Blacklist Pallet: Enhancing Security in Substrate-Based Blockchains

Hi there! Welcome to my very first blog post. My name is José, and I’m a Substrate engineer currently working at BlockDeep Labs. Previously, I had the incredible opportunity to work at Parity Technologies, where I honed my skills in blockchain development and Substrate.

This post is particularly special to me because it showcases the very first Substrate pallet I ever wrote — the Blacklist Pallet. I designed it to be simple yet effective, and it holds a lot of sentimental value as a foundational milestone in my career as a blockchain developer.

Why I Created the Blacklist Pallet

The idea for this pallet came to me when I noticed something curious: Substrate already has a Whitelist Pallet, but there was no equivalent for managing blacklists. This observation sparked a thought—why not create a complementary solution? With that, I set out to write my first pallet, keeping the scope straightforward to ensure it would be useful without overcomplicating things.

The result? A lightweight and flexible tool for enhancing security in Substrate-based blockchains.

What Does the Blacklist Pallet Do?

The Blacklist Pallet allows administrators to restrict specific accounts from performing certain actions within the network. By enabling a configurable origin—typically the Root origin—to manage a blacklist, this pallet strengthens the security framework of any blockchain it is integrated into.

Key Features

• Account Blacklisting: Add accounts to a blacklist to prevent them from executing designated actions.
• Event Emission: Emit an AccountBlacklisted event when an account is blacklisted, providing transparency.
• Blacklist Removal: Remove accounts from the blacklist and emit a BlacklistedAccountRemoved event.

How It Works

Here’s a quick breakdown of the extrinsics (or dispatchable functions) in the pallet:

1. blacklist_account: Adds an account to the blacklist.

   • Parameters:
     • origin: Must be a Root origin or relevant governance.
     • accountId: The account to blacklist.
   • Errors:
     • AccountAlreadyBlacklisted: The account is already blacklisted.

2. remove_blacklisted_account: Removes an account from the blacklist.

   • Parameters:
     • origin: Must be a Root origin.
     • accountId: The account to remove.
   • Errors:
     • AccountNotBlacklisted: The account is not on the blacklist.

Why It Matters

This pallet is a simple yet powerful addition to the Substrate ecosystem. It helps maintain the integrity of a blockchain by enabling administrators to manage blacklists effectively. Whether you're building a permissioned or permissionless network, having a blacklist option is a practical tool for addressing security concerns.

How to Integrate the Blacklist Pallet

If you'd like to try out the Blacklist Pallet in your own Substrate-based blockchain, here’s how to get started:

1. Update Dependencies: Add the following to your Cargo.toml:

   [dependencies]
   pallet-blacklist = { version = "1.0.0", default-features = false, git = "https://github.com/Moliholy/pallet-blacklist.git" }
   

2. Configure the Pallet: Implement the pallet_blacklist::Config for your runtime:

impl pallet_blacklist::Config for Runtime {
    type RuntimeEvent = RuntimeEvent;
    type BlacklistingOrigin = EnsureRoot<AccountId>;
    type WeightInfo = ();  // compute the actual weights!
}

3. Include It in the Runtime: Add the pallet to your runtime via the construct_runtime! macro:

construct_runtime! {
    pub struct Runtime {
        // -- snip --
        Blacklist: pallet_blacklist,
    }
}