Anti-Sybil Idea

Moonbound Anti-Sybil Protection Overview

Objective: Prevent wallet splitting and automated Sybil attacks during the Moonbound bonding curve sale, without introducing friction for real users.

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The Problem: To enforce a 10% per-wallet token holding cap, we must deter attackers from:

• Spinning up multiple wallets

• Rapidly approving and buying tokens in batches

Because Kaspa's EVM Layer 2 runs at 10 blocks per second, attackers can exploit fast wallet rotations if not restricted properly.

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Solution Summary: We implement a short, block-based delay between a user's first approval of wKAS and their first buy from the bonding curve. This delay prevents bots from performing approve + buy actions within the same block or rapid sequence.

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How It Works:

1. Track First Approval Block

mapping(address => uint256) public firstApprovalBlock;

function registerApproval() external {
    if (firstApprovalBlock[msg.sender] == 0) {
        firstApprovalBlock[msg.sender] = block.number;
    }
}

1. Enforce a Short Delay Before Buying

uint256 constant APPROVE_DELAY = 25; // ~2.5 seconds (Kaspa L2 runs at 10 blocks/sec)

function buy(uint256 amount) external {
    require(tx.origin == msg.sender, "No contract wallets allowed");

    if (firstApprovalBlock[msg.sender] > 0 && lastBuyBlock[msg.sender] == 0) {
        require(
            block.number > firstApprovalBlock[msg.sender] + APPROVE_DELAY,
            "Please wait ~2.5s after approving before buying"
        );
    }

    lastBuyBlock[msg.sender] = block.number;

    // Proceed with bonding curve logic
}

1. Track Buyers

mapping(address => uint256) public lastBuyBlock;

This ensures that only first-time buyers are subject to the delay. Subsequent buys from the same wallet are not restricted.

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Benefits:

• Blocks same-block approve+buy combos

• Disrupts Sybil bots using wallet cycling

• Invisible to real users (a 2.5s delay fits naturally into normal UX)

• No off-chain dependencies or wKAS contract modification

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Frontend Integration:

• After user approves wKAS, call registerApproval() in the same or next transaction

• Display an optional note: "Your approval was registered. Please wait 2–3 seconds before buying."

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Result: With just one additional mapping and a lightweight timing check, Moonbound gains powerful on-chain Sybil resistance tailored to Kaspa's high-speed L2 — without compromising UX for real users.