Signature Distributor

Introduction

The EDDSA Distributor program provides signature-based token distribution using EDDSA signatures for claim verification. This approach offers an alternative to Merkle tree-based distributors, allowing for more flexible and dynamic claim authorizations.

🚀 Quick Start

What is an EDDSA Distributor?

An EDDSA Distributor is a smart contract system that enables efficient token distribution using signature verification. Instead of storing a Merkle tree root, it uses cryptographic signatures from an authorized signer to validate claims, offering greater flexibility for dynamic distributions.

Key Benefits

• ✅ Dynamic Claims - No need to generate Merkle trees in advance

• ✅ Signature-Based - Claims authorized via EDDSA signatures

• ✅ Batch Processing - Process multiple claims in one transaction

Key Differences from Merkle Distributors

Feature	Merkle Distributor	EDDSA Distributor
Verification	Merkle proofs	EDDSA signatures
Data Storage	Merkle root	Authorized signer
Claim Data	Fixed at deployment	Dynamic per claim
Gas Cost	Higher for setup	Higher per claim
Flexibility	Limited	High

📋 System Overview

Account Structure

Storage Pattern

A contract has one config storage account, which stores the contract admin's account address and the default fee collector's deployment address. This account will also store a new admin's account address for secure two-step ownership transfers.

pub struct Config {
  pub admin: Pubkey,
  pub new_admin: Pubkey,
  pub default_fee_collector: Pubkey,
}

An EDDSA Distributor deployment can manage multiple airdrops. Airdrops use the following storage pattern:

pub struct Airdrop {
  pub owner: Pubkey,
  pub authorized_signer: Pubkey,
  pub token: Pubkey,
  pub start_time: u64,
  pub end_time: u64,
  pub fee_collector: Pubkey,
  pub fee_token: Pubkey,
  pub paused: bool,
}

Claim Mechanism

Claim support with signature verification:

pub fn claim(
  ctx: Context<Claim>,
  project_id: String,
  recipient: Pubkey,
  user_claim_id: [u8; 32],
  group: [u8; 32],
  user_claim_data: EDDSADistributorData,
  signature: Vec<u8>
) -> Result<()>

Security Features

• ECDSA signature verification

• Pausable functionality

• Reentrancy protection

• Claim ID account initialization to prevent double claims

Key Functions

Function	Description
initialize()	Initialize an airdrop, create required accounts
setBaseParams()	Sets token, time window, and authorized signer
claim()	Processes batch claims with signatures
togglePause()	Emergency pause functionality
deposit()	Deposit tokens to be airdropped

🔌 Distributor Variants

EDDSADistributor

Standard implementation for token distribution.

Data Structure:

pub struct EDDSADistributorData {
  pub claimable_timestamp: u64,
  pub claimable_amount: u64,
}

Key Features:

• Supports both SPL and SPL2022 tokens

• Time-locked claims based on claimable_timestamp

• Standard withdrawal function for unclaimed tokens

FungibleTokenWithFeesEDDSADistributor

Extension that includes fee data in the claim structure.

Data Structure:

pub struct EDDSADistributorData {
  pub claimable_timestamp: u64,
  pub claimable_amount: u64,
  pub fees: u64,
}

Key Features:

• Fees encoded in claim data

• Batch fee collection

• Mandatory fee collector configuration

• Custom fee amounts per claim

💰 Fee System

Overview

The fee system provides flexible fee collection for claims.

Components

1. Fee Collector - External FeeCollector program that calculates and manages vault accounts

2. Fee Token - Native or SPL token for fees

3. Vault Accounts - Program Derived Accounts (PDAs) for holding fee tokens

Fee Implementations

1. Fixed Fee - Base implementation charges per claim or batch

2. Custom Fee - Extension allows per-claim fee amounts

🔒 Security

Access Control

Role	Permissions
Program Admin	Set fee collector, transfer program admin
Airdrop Owner	Set parameters, toggle pause, configure signer
Authorized Signer	Sign claim authorizations
Users	Submit claims with valid signatures

Security Features

• Signature Verification - ECDSA signature validation

• Pausable - Emergency stop functionality

• Reentrancy Guards - Protection against reentrancy attacks

• Claim Tracking - Prevents double claiming

• Time Windows - Enforced distribution periods

📡 Events & Errors

Events

Event	Description
Initialized	Successful aidrop initialization
ClaimDelegateSet	Successful claim delegate set
Claimed	Successful token claim

Errors

Error	Condition
UnsupportedOperation	Operation not allowed
TimeInactive	Outside distribution window
InvalidSignature	Signature verification failed
OutsideClaimableTimeRange	Outside claim window
NotOwner	Unpermissioned account trying to call an owner-permissioned function
NotProgramAdmin	Unpermissioned account trying to call a program admin-permissioned function
NotPermissioned	Unpermissioned account trying to receive program admin status
InvalidFeeCollector	Provided fee collector account is incorrect
Paused	Airdrop has been paused