Key-Value store Developer Tutorial

Learn how to use SecretPath on EVM to encrypt payloads.

Overview

SecretPath seamlessly handles encrypted payloads on the EVM, which means EVM developers can use SecretPath to encrypt and decrypt messages cross-chain with little-to-no Rust experience required.

This tutorial explains how to upload your own Key-value store contract on Secret Network, which you can use to encrypt values on the EVM, as well as how to encrypt payloads and transmit them cross-chain. After this tutorial, you will have the tools you need to use SecretPath to encrypt messages on any EVM-compatible chain.

Getting Started

To get started, clone the SecretPath tutorials repository:

git clone https://github.com/SecretFoundation/Secretpath-tutorials

Configuring Environment Variables

cd into encrypted-payloads/evm-contract

cd encrypted-payloads/evm-contract

Install the dependencies:

npm install

Create an env file and add your:

  • EVM wallet private key

  • Infura API endpoint (Sepolia testnet)

See here for a properly configured example env file

Get sepolia tokens from faucet:

This tutorial is for Sepolia testnet, but there are 10+ chains currently configured that are also compatible by simply swapping out the SecretPath gateway address.

Now that your developer environment is properly configured, you're ready to encrypt your first payload with SecretPath!

Upload the Key value store contract on Secret Network

cd into encrypted-payloads/secret-contract

cd encrypted-payloads/secret-contract

Compile the Secret Network key value store contract:

RUSTFLAGS='-C link-arg=-s' cargo build --release --target wasm32-unknown-unknown

cd into secret-contract/node

cd secret-contract/node

Install the dependencies:

npm i

Open the upload.js file and review the instantiate message at line 70:

 let init = {
    gateway_address: gatewayAddress,
    gateway_hash: gatewayHash,
    gateway_key: gatewayPublicKeyBytes,
  };
  • gatewayAddress is the SecretPath gateway contract address for testnet

  • gatewayHash is the SecretPath gateway contract hash for testnet

  • gatewayKey is public key used for SecretPath encryption on Secret testnet

These three parameters remain constant and must be passed for every Secret Network contract that implements SecretPath. They can be found here for testnet.

To upload and instantiate the contract, run node upload:

node upload

Upon successful upload, a contractHash and address will be returned:

codeId:  5701
Contract_hash: "6311a3f85261fc720d9a61e4ee46fae1c8a23440122b2ed1bbcebf49e3e46ad2"
contract_address:  "secret1j0gpu6tlwnc9fw55wcfsfuml00kqpcnqz7dck7"

Encrypt a payload

Now that you have your key value store smart contract uploaded on Secret Network, let's use it to store encrypted messages. Most of the ECDH cryptography has been abstracted away so there are only a few values you need to change.

cd into encrypted-payloads/evm-contract:

cd encrypted-payloads/evm-contract

Open encrypt.js in evm-contract/scripts and navigate to lines 43-49.

Update the routing_contract and routing_code_hash to the contract address and codehash of the Secret Network smart contract that you instantiated:

  //EVM gateway contract address
  const publicClientAddress = "0x3879E146140b627a5C858a08e507B171D9E43139";

  //the contract you want to call in secret
  const routing_contract = "secret1z9wdcmxdad2c07m6m8l5cwvrhmwrkexp64fck0";
  const routing_code_hash =
    "6311a3f85261fc720d9a61e4ee46fae1c8a23440122b2ed1bbcebf49e3e46ad2";

publicClientAddress is the gateway contract address for Sepolia, which is found in Secret's gateway contract docs here.

Next, update lines 73-77 with the EVM wallet address associated with the private key in your env file (myAddress), a key (any string of your choosing), a value, (any string of your choosing), and a viewing_key (any string of your choosing).

value is the the data that you want to encrypt, key and viewing_key are parameters you pass to encrypt the value.

 const myAddress = "";
  const key = "";
  const value = "";
  const viewing_key = "";

Next, you are going to set the handle variable to call the store_value function inside of the Secret contract that you instantiated earlier. You do this with line 80, which corresponds to the store_value function in the Secret contract:

    let handle = msg.handle.as_str();
    match handle {
        "store_value" => store_value(deps, env, msg.input_values, msg.task, msg.input_hash),
        "retrieve_value" => retrieve_value(deps, env, msg.input_values, msg.task, msg.input_hash),
        _ => Err(StdError::generic_err("invalid handle".to_string())),

Once you have decided upon these parameters, simply run encrypt.js:

npx hardhat run scripts/encrypt.js --network sepolia

Upon successful encryption, your payload hash will be returned:

Payload Hash: 0xcd51559a345f37217a41757cdbe16e7b816f150d8b29ed1bf59fe6b7b5dbfbff
Payload Signature: 0x985085588613f7cf7cd8ca117b747ed8d9f604ee3fca9a66c3cee1ebeb1bc38f17fbe8e63438715f7f479e4e178b4022afbcf0b3967156b8ea1d84ebce7d3f321c
Recovered public key: 0x0423d8d8b518902cd6b0da592af0424719c355a724687cb74d96bd1171eb148edb87f3e9ca67f9ccecde109333461162af4dc09b33604c7e82242852a7142878ec
Verify this matches the user address: 0x49e01eb08bBF0696Ed0df8cD894906f7Da635929
_userAddress: 0x49e01eb08bBF0696Ed0df8cD894906f7Da635929
  _routingInfo: secret1pfg825wflcl40dqpd3yj96zhevnlxkh35hedks 
  _payloadHash: 0xcd51559a345f37217a41757cdbe16e7b816f150d8b29ed1bf59fe6b7b5dbfbff 
  _info: {"user_key":"0x02b7411401eb089a091ba7680e7f13588d8d297a4ad215aafd24eda0a397d50a2e","user_pubkey":"0x0423d8d8b518902cd6b0da592af0424719c355a724687cb74d96bd1171eb148edb87f3e9ca67f9ccecde109333461162af4dc09b33604c7e82242852a7142878ec","routing_code_hash":"fc5007efb0580334be20142a3011f34101be681eaa2fe277ee429f4d76107876","task_destination_network":"pulsar-3","handle":"store_value","nonce":"0x3a813b8a8061a79758a2b69d","payload":"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","payload_signature":"0x985085588613f7cf7cd8ca117b747ed8d9f604ee3fca9a66c3cee1ebeb1bc38f17fbe8e63438715f7f479e4e178b4022afbcf0b3967156b8ea1d84ebce7d3f321c","callback_gas_limit":300000}
  _callbackAddress: 0x3879e146140b627a5c858a08e507b171d9e43139,
  _callbackSelector: 0x373d450c ,
  _callbackGasLimit: 300000
Transaction sent! Hash: 0x7cba6149de15e42d0198a1c33548dbcaf6e1142c778f665f62b25a21e9475b57
Transaction confirmed! Block Number: 5412596

Congrats, you have encrypted your first cross-chain payload with SecretPath!

Decrypt your payload

To decrypt your encrypted payload, cd into secret-contract/node

cd secret-contract/node

Open decrypt.js and update lines 8-9 with your key and viewing-key:

  const key = "secret sauce";
  const viewing_key = "my viewing key";

Then run node decrypt:

node decrypt 

Your decrypted payload will be returned:

{
  key: 'secret sauce',
  value: 'secret to the moon',
  message: 'Retrieved value successfully'
}

Congrats! You have now used SecretPath to encrypt and decrypt cross-chain payloads! ๐Ÿ”ฅ

Summary

SecretPath is a powerful addition to Secret Networkโ€™s cross-chain messaging capabilities. Along with IBC and Axelar GMP, and eventually to be joined by additional bridging technologies like Wormhole and Union, it enables groundbreaking new use-cases for Web3 applications by providing access to confidential computation. This facilitates novel applications such as private voting for DAOs, secure random number generation, confidential data access control via NFTs, encrypted DeFi order books, sealed-bid auctions, and storing encrypted data.

We also encourage developers to check out our grants program to get funding for building with SecretPath, and to join our Discord and Telegram to get involved with our community. You can also contact our team directly if you have any questions about building on Secret.

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