🪙 Decentralized Stable Coin (MDSC) — USD Pegged Stablecoin

A decentralized stablecoin protocol pegged to USD, inspired by Maker-like mechanics and built with Vyper + Moccasin + Boa.

✅ Overcollateralized
✅ Multi-collateral (WETH + WBTC)
✅ Chainlink-style price feeds
✅ Liquidation mechanism with bonus
✅ Unit tests + fuzz/invariant testing (80%+ coverage)
✅ Deployed on zkSync Sepolia

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✨ Features

🪙 Stablecoin Token (MDSC)

• ERC20 compliant
• Minting controlled via minters
• Ownership controlled via ownable
• Built using Snekmate ERC20

Contract: Decentralized Stable Coin (MDSC)
Symbol: MDSC
Decimals: 18

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⚙️ Engine Contract (DSCEngine)

The protocol logic lives here.

Supports:

• 🏦 Deposit collateral (WETH/WBTC)
• 💵 Mint DSC against collateral
• 🔥 Burn DSC to reduce debt
• 💳 Redeem collateral
• 🧨 Liquidations for unhealthy positions

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🧠 Protocol Rules / Risk Parameters

Parameter	Value
Liquidation Threshold	50%
Liquidation Bonus	10%
Min Health Factor	1.0
Precision	1e18
Feed Precision	1e8
Additional Feed Precision	1e10

✅ Users must remain safely overcollateralized.
⚠️ If health factor < 1e18, position can be liquidated.

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🏗️ Architecture

User
 │
 │ deposit_collateral()
 ▼
DSCEngine  ─────────────► Price Feeds (ETH/USD, BTC/USD)
 │
 │ mint_dsc()
 ▼
DecentralizedStableCoin (MDSC)

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📦 Contracts

1) decentralized_stable_coin.vy

• ERC20 token based on Snekmate

• Supports:

  • mint(address,uint256)
  • burn_from(address,uint256)
  • set_minter(address,bool)
  • ownership transfer

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2) dsc_engine.vy

Core protocol engine:

• Deposit collateral

• Mint/burn DSC

• Health factor checks

• Liquidations

• Oracle price conversions:

  • get_usd_value(token, amount)
  • get_token_amount_from_usd(token, usd_amount_in_wei)

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3) oracle_lib.vy

Oracle safety layer ✅

Prevents stale price usage:

• enforces timeout (3 hours)
• reverts when feed stale
• renders protocol unusable when oracles stale (by design)

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🧪 Testing

This project includes:

✅ Unit Tests

• Token mint/burn logic
• Collateral deposit/redemption
• Health factor invariants
• Liquidation functionality

🧬 Fuzz + Invariant Tests

• Stateful fuzzing using Hypothesis

• Randomized sequences:

  • deposits
  • mint
  • redeem
  • price updates

• Invariant examples:

  • protocol collateral value ≥ total DSC supply

📊 Coverage

✅ 80%+ test coverage (unit + fuzz/invariant)

Run tests:

mox test

Run tests with prints:

mox test -s

Run coverage:

mox test --coverage

Run only fuzz tests:

mox test -s -k fuzz

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🛠️ Build

Compile all contracts:

mox build

Artifacts generated in:

out/

Example:

• out/decentralized_stable_coin.json
• out/dsc_engine.json
• out/oracle_lib.json

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🚀 Deploy (zkSync Sepolia)

Network:

• zkSync Sepolia
• Chain ID: 300
• RPC: https://sepolia.era.zksync.dev
• Explorer: https://explorer.sepolia.era.zksync.dev

Deploy Command

mox run script/deploy.py --network zksync-sepolia

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✅ Deployed Addresses (zkSync Sepolia)

🪙 MDSC Token

• DecentralizedStableCoin (MDSC) 0x1c17Dbb3Cd79d37fBbE0a9d2F462b09717d77D3b

⚙️ DSCEngine

• DSCEngine 0x7FaE3141341Ca5985D5412102C3C66965866BC52

🏦 Collateral Tokens

• WBTC 0xE544cAd11e108775399358Bd0790bb72c9e3AD9E

• WETH 0xdd13E55209Fd76AfE204dBda4007C227904f0a81

📈 Price Feeds

• BTC/USD Price Feed 0x95Bc57e794aeb02E4a16eff406147f3ce2531F83

• ETH/USD Price Feed 0xfEefF7c3fB57d18C5C6Cdd71e45D2D0b4F9377bF

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🔐 Post-Deployment Setup (zkSync workaround)

Boa/Moccasin zkSync env currently cannot perform some contract calls due to simulate incompatibility, so minter/ownership setup is done using cast.

✅ Set DSCEngine as minter

cast send 0x1c17Dbb3Cd79d37fBbE0a9d2F462b09717d77D3b \
  "set_minter(address,bool)" 0x7FaE3141341Ca5985D5412102C3C66965866BC52 true \
  --rpc-url https://sepolia.era.zksync.dev \
  --private-key $PRIVATE_KEY

✅ Transfer ownership to DSCEngine

cast send 0x1c17Dbb3Cd79d37fBbE0a9d2F462b09717d77D3b \
  "transfer_ownership(address)" 0x7FaE3141341Ca5985D5412102C3C66965866BC52 \
  --rpc-url https://sepolia.era.zksync.dev \
  --private-key $PRIVATE_KEY

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🧾 Project Commands Cheat Sheet

Action	Command
Build	mox build
Test	mox test
Coverage	mox test --coverage
Deploy zkSync Sepolia	mox run script/deploy.py --network zksync-sepolia
Deploy local anvil	mox run script/deploy.py --network anvil

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🧑‍💻 Author

Made with ❤️ by Dhruv4ne

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📜 License

MIT