Shutter PREDICT

Shutter PREDICT is a decentralized application (dApp) built on Gnosis Chain, enabling users to threshold-encrypt predictions, commit them on-chain, and reveal them when a pre-specified time has passed. The encrypted predictions are safeguarded by Shutter's keyper network, ensuring privacy and integrity until the reveal time.

Why Do People Hash/Encrypt Their Predictions? You might have seen people tweet out hashes instead of their actual predictions. Here’s why:

• Protecting Valuable Insights: Sometimes predictions hold valuable insights that could move markets or influence opinions if they were made public too early. Encrypting them keeps these insights safe until the right moment.
• Avoiding Unwanted Influence: In scenarios like upcoming elections or other sensitive events, keeping predictions encrypted helps avoid swaying public opinion before the actual event occurs.

Here’s a great blog post on this: https://www.sharvesh.com/p/interpol-red-notice-for-cobie

But here’s the issue: People aren’t committed to this prediction. If in the future, it turns out they’re wrong, they’ll just not reveal the secret. What if there were a way to enforce decryption and reveal? The answer is quite simple: you don’t just post the hash, you post the actual encrypted message and you use threshold-encryption powered time-lock to enforce the decryption in a decentralized manner. That’s Shutter Predict.

Features

• Threshold Encryption: Encrypt predictions using Shutter's encryption mechanism.
• On-chain Commitment: Commit encrypted predictions to a smart contract on Gnosis Chain.
• Automated Decryption: The Shutter keyper network generates a decryption key at the scheduled reveal time.
• Prediction Explorer: View and verify predictions in the Shutter Prediction Explorer.
• Social Sharing: Share your predictions via a pre-filled Twitter post.

How It Works

1. Encrypt Your Prediction: Enter your prediction and specify a future reveal time.
2. Commit to Gnosis Chain: Once encrypted, commit your prediction to the blockchain.
3. Reveal After Time: After the reveal time passes, the Shutter keyper network decrypts your prediction, making it publicly accessible.

Technology Stack

• Frontend: HTML, CSS, JavaScript
• Blockchain: Gnosis Chain (smart contracts)
• Libraries:
  • ethers.js for blockchain interactions
  • axios for API requests
  • Custom Shutter encryption/decryption functions

Getting Started

Prerequisites

1. Install MetaMask or another Ethereum-compatible wallet.
2. Ensure you have access to the Gnosis Chain network and xDAI for transactions.

Running the App

1. Clone the repository.

   git clone https://github.com/pepae/ShutterPredict.git

2. Open the index.html file in your web browser.

3. Connect your wallet by clicking the Connect Wallet button.

4. Complete the 3-step process:

   • Step 1: Encrypt – Enter your prediction and encrypt it.
   • Step 2: Commit – Submit the encrypted prediction on-chain.
   • Step 3: Decrypt – Retrieve and decrypt the prediction after the reveal time.

Usage

Prediction Explorer

View past predictions using the built-in Shutter PREDICT Explorer. The explorer lists prediction details including ciphertext, plaintext (if revealed), reveal time, and status.

Sharing Predictions

After committing a prediction, you can share a pre-filled tweet with:

• The reveal time
• The first 10 characters of the ciphertext
• A link to view your prediction in the explorer

Network Configuration

If your wallet is not connected to Gnosis Chain, the app will prompt you to add the network with the following parameters:

{
  "chainId": "0x64",
  "chainName": "Gnosis Chain",
  "nativeCurrency": {
    "name": "xDAI",
    "symbol": "xDAI",
    "decimals": 18
  },
  "rpcUrls": ["https://rpc.gnosischain.com"],
  "blockExplorerUrls": ["https://gnosisscan.io"]
}

Smart Contract Details

• Contract Address: 0xd4194b8D3cB3CE825690a9Fb167a9e6E145a9d58
• Main Functions:
  • commitPrediction(bytes _encryptedData, uint256 _revealTime, string _shutterIdentity)
  • revealPrediction(uint256 _id, string _plaintext)

Compiling

solc \
    --output-dir=./solc_out/ \
    --base-path=./contracts \
    --include-path=lib \
    --combined-json=abi,bin,bin-runtime \
    contracts/PredictionContract.sol

Development

Structure

• index.html: Main prediction dApp interface
• explorer.html: Prediction Explorer page
• app.js: Core logic for wallet connection, encryption, and transaction handling
• explorer.js: Logic to display and manage predictions on the explorer page

Contributing

Feel free to submit issues and pull requests to improve the app. Contributions are welcome!