How to Burn Compressed Accounts

Guide to burn compressed accounts in Solana programs with full code examples.

Overview

Compressed accounts are permanently burned via CPI to the Light System Program.

Burning a compressed account

consumes the existing account hash, and
produces no output state.
A burned account cannot be reinitialized.

Find full code examples at the end for Anchor and native Rust.

Implementation Guide

This guide will cover the components of a Solana program that burns compressed accounts. Here is the complete flow to burn compressed accounts:

Program Setup

Dependencies, Constants, Compressed Account

Dependencies

Add dependencies to your program.

[dependencies]
light-sdk = "0.16.0"
anchor_lang = "0.31.1"

[dependencies]
light-sdk = "0.16.0"
borsh = "0.10.0"
solana-program = "2.2"

The light-sdk provides macros, wrappers and CPI interface to create and interact with compressed accounts.
Add the serialization library (borsh for native Rust, or use AnchorSerialize).

Constants

Set program address and derive the CPI authority PDA to call the Light System program.

declare_id!("rent4o4eAiMbxpkAM1HeXzks9YeGuz18SEgXEizVvPq");

pub const LIGHT_CPI_SIGNER: CpiSigner =
    derive_light_cpi_signer!("rent4o4eAiMbxpkAM1HeXzks9YeGuz18SEgXEizVvPq");

CPISigner is the configuration struct for CPI's to the Light System Program.

CPIs to the Light System program must be signed with a PDA derived by your program with the seed b"authority"
derive_light_cpi_signer! derives the CPI signer PDA for you at compile time.

Compressed Account

Define your compressed account struct.

#[event] // declared as event so that it is part of the idl.#[derive( Clone, Debug, Default, LightDiscriminator)]pub struct MyCompressedAccount { pub owner: Pubkey, pub message: String,}#[derive( Debug, Default, Clone, BorshSerialize, BorshDeserialize, LightDiscriminator,)]pub struct MyCompressedAccount { pub owner: Pubkey, pub message: String,}

You derive

the standard traits (Clone, Debug, Default),
borsh or AnchorSerialize to serialize account data, and
LightDiscriminator to implements a unique type ID (8 bytes) to distinguish account types. The default compressed account layout enforces a discriminator in its own field, .

The traits listed above are required for LightAccount. LightAccount wraps MyCompressedAccount in Step 3 to set the discriminator and create the compressed account's data.

Instruction Data

Define the instruction data with the following parameters:

pub fn burn_account<'info>(
    ctx: Context<'_, '_, '_, 'info, GenericAnchorAccounts<'info>>,
    proof: ValidityProof,
    account_meta: CompressedAccountMetaBurn,
    current_message: String,
) -> Result<()>

Validity Proof

Define proof to include the proof that the account exists in the state tree.
Clients fetch a validity proof with getValidityProof() from an RPC provider that supports ZK Compression (Helius, Triton, ...).

Specify input state

Define account_meta: CompressedAccountMetaBurn to reference the existing account for the Light System Program to nullify permanently:
- tree_info: PackedStateTreeInfo: References the existing account hash in the state tree.
- address: The account's derived address.

Burn does not specify an output state tree. CompressedAccountMetaBurn omits output_state_tree_index because no output state is created.

Current account data

Define fields to include the current account data passed by the client.
This depends on your program logic. This example includes current_message (or current_account in Native Rust).

Burn Compressed Account

Burn the compressed account permanently with LightAccount::new_burn(). No account can be reinitialized at this address in the future.

new_burn()

hashes the current account data as input state and
creates no output state to burn the account permanently.

let my_compressed_account = LightAccount::<MyCompressedAccount>::new_burn(
    &crate::ID,
    &account_meta,
    MyCompressedAccount {
        owner: ctx.accounts.signer.key(),
        message: current_message,
    },
)?;

Pass these parameters to new_burn():

&program_id: The program's ID that owns the compressed account.
&account_meta: The CompressedAccountMetaBurn from instruction data (Step 2) that identifies the existing account for the Light System Program to nullify permanently.
- Anchor: Pass &account_meta directly
- Native Rust: Pass &instruction_data.account_meta
Include the curent account data.
- Anchor: Build MyCompressedAccount with owner and message.
- Native Rust: Pass instruction_data.current_account directly.

The SDK creates:

A LightAccount wrapper that marks the account as burned permanently with no output state.

new_burn() hashes the input state. The Light System Program verifies the input hash and nullifies it permanently in Step 4.

Light System Program CPI

The Light System Program CPI burns the compressed account permanently.

The Light System Program

validates the account exists in state tree with the validity,
nullifies the existing account hash permanently, and
creates no output state.

let light_cpi_accounts = CpiAccounts::new(
    ctx.accounts.signer.as_ref(),
    ctx.remaining_accounts,
    crate::LIGHT_CPI_SIGNER,
);

LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, proof)
    .with_light_account(my_compressed_account)?
    .invoke(light_cpi_accounts)?;

Set up CpiAccounts::new():

CpiAccounts::new() parses accounts for the CPI call to Light System Program.

Pass these parameters:

ctx.accounts.signer.as_ref(): the transaction signer
ctx.remaining_accounts: Slice with [system_accounts, ...packed_tree_accounts]. The client builds this with PackedAccounts and passes it to the instruction.
&LIGHT_CPI_SIGNER: Your program's CPI signer PDA defined in Constants.

let (signer, remaining_accounts) = accounts
    .split_first();

let cpi_accounts = CpiAccounts::new(
    signer,
    remaining_accounts,
    LIGHT_CPI_SIGNER
);

LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, instruction_data.proof)
    .with_light_account(my_compressed_account)?
    .invoke(cpi_accounts)?;

Set up CpiAccounts::new():

CpiAccounts::new() parses accounts for the CPI call to Light System Program.

Pass these parameters:

signer: account that signs and pays for the transaction
remaining_accounts: Slice with [system_accounts, ...packed_tree_accounts]. The client builds this with PackedAccounts.
- split_first() extracts the fee payer from the accounts array to separate it from the Light System Program accounts needed for the CPI.
&LIGHT_CPI_SIGNER: Your program's CPI signer PDA defined in Constants.

System Accounts List

Verifies validity proofs, compressed account ownership checks, cpis the account compression program to update tree accounts

CPI Signer

- PDA to sign CPI calls from your program to Light System Program - Verified by Light System Program during CPI - Derived from your program ID

Registered Program PDA

- Access control to the Account Compression Program

- Logs compressed account state to Solana ledger. Only used in v1. - Indexers parse transaction logs to reconstruct compressed account state

Signs CPI calls from Light System Program to Account Compression Program

- Writes to state and address tree accounts - Client and the account compression program do not interact directly.

Invoking Program

Your program's ID, used by Light System Program to: - Derive the CPI Signer PDA - Verify the CPI Signer matches your program ID - Set the owner of created compressed accounts

Solana System Program to transfer lamports

Build the CPI instruction:

new_cpi() initializes the CPI instruction with the proof to prove the account exists in the state tree - defined in the Instruction Data (Step 2).
with_light_account adds the LightAccount wrapper configured to burn the account - defined in Step 3.
invoke(light_cpi_accounts) calls the Light System Program with CpiAccounts.

Full Code Example

The example programs below implement all steps from this guide. Make sure you have your developer environment set up first.

npm -g i @lightprotocol/[email protected]
light init testprogram

For help with debugging, see the Error Cheatsheet.

Find the source code here.

#![allow(unexpected_cfgs)]
#![allow(deprecated)]

use anchor_lang::{prelude::*, AnchorDeserialize, AnchorSerialize};
use light_sdk::{
    account::LightAccount,
    address::v1::derive_address,
    cpi::{v1::CpiAccounts, CpiSigner},
    derive_light_cpi_signer,
    instruction::{account_meta::CompressedAccountMetaBurn, PackedAddressTreeInfo, ValidityProof},
    LightDiscriminator,
};

declare_id!("BJhPWQnD31mdo6739Mac1gLuSsbbwTmpgjHsW6shf6WA");

pub const LIGHT_CPI_SIGNER: CpiSigner =
    derive_light_cpi_signer!("BJhPWQnD31mdo6739Mac1gLuSsbbwTmpgjHsW6shf6WA");

#[program]
pub mod burn {

    use super::*;
    use light_sdk::cpi::{
        v1::LightSystemProgramCpi, InvokeLightSystemProgram, LightCpiInstruction,
    };

    /// Setup: Creates a compressed account
    pub fn create_account<'info>(
        ctx: Context<'_, '_, '_, 'info, GenericAnchorAccounts<'info>>,
        proof: ValidityProof,
        address_tree_info: PackedAddressTreeInfo,
        output_state_tree_index: u8,
        message: String,
    ) -> Result<()> {
        let light_cpi_accounts = CpiAccounts::new(
            ctx.accounts.signer.as_ref(),
            ctx.remaining_accounts,
            crate::LIGHT_CPI_SIGNER,
        );

        let (address, address_seed) = derive_address(
            &[b"message", ctx.accounts.signer.key().as_ref()],
            &address_tree_info
                .get_tree_pubkey(&light_cpi_accounts)
                .map_err(|_| ErrorCode::AccountNotEnoughKeys)?,
            &crate::ID,
        );

        let mut my_compressed_account = LightAccount::<MyCompressedAccount>::new_init(
            &crate::ID,
            Some(address),
            output_state_tree_index,
        );

        my_compressed_account.owner = ctx.accounts.signer.key();
        my_compressed_account.message = message.clone();

        msg!(
            "Created compressed account with message: {}",
            my_compressed_account.message
        );

        LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, proof)
            .with_light_account(my_compressed_account)?
            .with_new_addresses(&[address_tree_info.into_new_address_params_packed(address_seed)])
            .invoke(light_cpi_accounts)?;

        Ok(())
    }

    /// Burns a compressed account permanently
    pub fn burn_account<'info>(
        ctx: Context<'_, '_, '_, 'info, GenericAnchorAccounts<'info>>,
        proof: ValidityProof,
        account_meta: CompressedAccountMetaBurn,
        current_message: String,
    ) -> Result<()> {
        let light_cpi_accounts = CpiAccounts::new(
            ctx.accounts.signer.as_ref(),
            ctx.remaining_accounts,
            crate::LIGHT_CPI_SIGNER,
        );

        let my_compressed_account = LightAccount::<MyCompressedAccount>::new_burn(
            &crate::ID,
            &account_meta,
            MyCompressedAccount {
                owner: ctx.accounts.signer.key(),
                message: current_message,
            },
        )?;

        msg!("Burning compressed account permanently");

        LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, proof)
            .with_light_account(my_compressed_account)?
            .invoke(light_cpi_accounts)?;

        Ok(())
    }
}

#[derive(Accounts)]
pub struct GenericAnchorAccounts<'info> {
    #[account(mut)]
    pub signer: Signer<'info>,
}

#[event]
#[derive(Clone, Debug, Default, LightDiscriminator)]
pub struct MyCompressedAccount {
    pub owner: Pubkey,
    pub message: String,
}

Find the source code here.

#![allow(unexpected_cfgs)]

#[cfg(any(test, feature = "test-helpers"))]
pub mod test_helpers;

use borsh::{BorshDeserialize, BorshSerialize};
use light_macros::pubkey;
use light_sdk::{
    account::sha::LightAccount,
    address::v1::derive_address,
    cpi::{
        v1::{CpiAccounts, LightSystemProgramCpi},
        CpiSigner, InvokeLightSystemProgram, LightCpiInstruction,
    },
    derive_light_cpi_signer,
    error::LightSdkError,
    instruction::{account_meta::CompressedAccountMetaBurn, PackedAddressTreeInfo, ValidityProof},
    LightDiscriminator,
};
use solana_program::{
    account_info::AccountInfo, entrypoint, program_error::ProgramError, pubkey::Pubkey,
};

pub const ID: Pubkey = pubkey!("CFWrQ8za2yT1xH8yBjYvsDUCWnBH7vXtyVJwqoX5FcNg");
pub const LIGHT_CPI_SIGNER: CpiSigner = derive_light_cpi_signer!("CFWrQ8za2yT1xH8yBjYvsDUCWnBH7vXtyVJwqoX5FcNg");

#[cfg(not(feature = "no-entrypoint"))]
entrypoint!(process_instruction);

#[derive(Debug, BorshSerialize, BorshDeserialize)]
pub enum InstructionType {
    Create,
    Burn,
}

#[derive(Debug, BorshSerialize, BorshDeserialize)]
pub struct CreateInstructionData {
    pub proof: ValidityProof,
    pub address_tree_info: PackedAddressTreeInfo,
    pub output_state_tree_index: u8,
    pub message: String,
}

#[derive(Debug, BorshSerialize, BorshDeserialize)]
pub struct BurnInstructionData {
    pub proof: ValidityProof,
    pub account_meta: CompressedAccountMetaBurn,
    pub current_account: MyCompressedAccount,
}

#[derive(Debug, Default, Clone, BorshSerialize, BorshDeserialize, LightDiscriminator)]
pub struct MyCompressedAccount {
    pub owner: Pubkey,
    pub message: String,
}

pub fn process_instruction(
    _program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> Result<(), ProgramError> {
    let (instruction_type, rest) = instruction_data
        .split_first()
        .ok_or(ProgramError::InvalidInstructionData)?;

    match InstructionType::try_from_slice(&[*instruction_type])
        .map_err(|_| ProgramError::InvalidInstructionData)?
    {
        InstructionType::Create => create(accounts, rest)?,
        InstructionType::Burn => burn(accounts, rest)?,
    }

    Ok(())
}

fn create(accounts: &[AccountInfo], instruction_data: &[u8]) -> Result<(), LightSdkError> {
    let instruction_data =
        CreateInstructionData::try_from_slice(instruction_data).map_err(|_| LightSdkError::Borsh)?;

    let signer = accounts.first().ok_or(ProgramError::NotEnoughAccountKeys)?;

    let light_cpi_accounts = CpiAccounts::new(
        signer,
        &accounts[1..],
        LIGHT_CPI_SIGNER
    );

    let (address, address_seed) = derive_address(
        &[b"message", signer.key.as_ref()],
        &instruction_data
            .address_tree_info
            .get_tree_pubkey(&light_cpi_accounts)
            .map_err(|_| ProgramError::NotEnoughAccountKeys)?,
        &ID,
    );

    let new_address_params = instruction_data
        .address_tree_info
        .into_new_address_params_packed(address_seed);

    let mut my_compressed_account = LightAccount::<MyCompressedAccount>::new_init(
        &ID,
        Some(address),
        instruction_data.output_state_tree_index,
    );
    my_compressed_account.owner = *signer.key;
    my_compressed_account.message = instruction_data.message;

    LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, instruction_data.proof)
        .with_light_account(my_compressed_account)?
        .with_new_addresses(&[new_address_params])
        .invoke(light_cpi_accounts)?;

    Ok(())
}

fn burn(accounts: &[AccountInfo], instruction_data: &[u8]) -> Result<(), LightSdkError> {
    let instruction_data =
        BurnInstructionData::try_from_slice(instruction_data).map_err(|_| LightSdkError::Borsh)?;

    let (signer, remaining_accounts) = accounts
        .split_first()
        .ok_or(ProgramError::InvalidAccountData)?;

    let cpi_accounts = CpiAccounts::new(
        signer,
        remaining_accounts,
        LIGHT_CPI_SIGNER
    );

    let my_compressed_account = LightAccount::<MyCompressedAccount>::new_burn(
        &ID,  // Now the burn program owns the account since it created it
        &instruction_data.account_meta,
        instruction_data.current_account,
    )?;

    LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, instruction_data.proof)
        .with_light_account(my_compressed_account)?
        .invoke(cpi_accounts)?;

    Ok(())
}

Next Steps

Build a client for your program or get an overview on all compressed account operations.

Client Library

Guides

Last updated 1 day ago

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