> ## Documentation Index
> Fetch the complete documentation index at: https://docs.peaq.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# DID

The following provides **simplified**, step-by-step instructions for interacting with the EVM-compatible Decentralized Identifier (DID) **smart contract** on the peaq network.
It covers how to execute the primary functions of the DID smart contract. This documentation applies to **both** peaq and agung networks.

The precompile is integrated into our JavaScript SDK, serving as the underlying mechanism that triggers the execution of the **corresponding** extrinsic on the substrate side.
This seamless integration ensures **interoperability** between the EVM environment and our substrate-based framework.

## Prerequisites

* Basic understanding of blockchain, EVM, and DID concepts.
* Using the Remix IDE with MetaMask configured to interact with a peaq network.
* You have token funds available in the wallet connected to the a peaq network.

## Instructions

### 1. Setup Remix IDE

* Open the [Remix website](https://remix.ethereum.org/).
* Create a new blank workspace for the precompiles.

### 2. Create a New File

* In your Remix workspace, create a new file named `DID.sol`.
* Copy the content of the DID precompile file from the peaq network node precompile page and paste it into the `DID.sol` file.
  The precompile is found at the [peaq node source code](https://github.com/peaqnetwork/peaq-network-node/blob/dev/precompiles/peaq-did/did.sol).

### 3. Compile the Contract

* Compile the `DID.sol` file by clicking on the **Solidity Compiler** tab and selecting the appropriate compiler version.
* Ensure the compilation is successful and generates the ABI file needed for interacting with the smart contract.

### 4. Deploy and Interact with the Contract

1. Under the **Deploy and Run Transactions** tab, select **Injected Provider - MetaMask** as the environment.
2. Ensure your chain ID matches the selected network (peaq/agung).
3. Choose the account with sufficient token funds.
4. Set the contract address to `0x0000000000000000000000000000000000000800` (found at the top of the copied file).
5. Click **At Address** to load the deployed contract into the interface.

On the bottom left your the Remix interface you will get the following functions you can interact with:

<img src="https://mintcdn.com/peaq/bfUMfJGiNN2sOYvn/assets/img/did-precompile-1.png?fit=max&auto=format&n=bfUMfJGiNN2sOYvn&q=85&s=0414ab5d9c36ef94612d489a0d48796f" alt="did-precompile-1" width="402" height="973" data-path="assets/img/did-precompile-1.png" />

### 5. Interact with the Functions

#### addAttribute

To add a DID Document as a value please generate the value via the Serialized DID section in the [JavaScript SDK](/peaqchain/sdk-reference/javascript/serialized-did) Reference. Otherwise you can set your own custom data to set with.

* **Parameters:**
  * `did_account`: Public hex key (e.g., `0x…`).
  * `name`: Hex representation of the DID name data.
  * `value`: Hex representation of the DID value data.
  * `validity_for`: Set to 0.
* **Behavior:** Adds a new attribute to the DID.
* **Result:**
  * Verify the transaction in MetaMask or Remix.
  * Confirm EVM logs in the Remix terminal.
  * Check for the attribute on the Substrate side via recent events in polkadot.js.

#### removeAttribute

* **Parameters:**
  * `did_account`: Public hex key (e.g., `0x…`).
  * `name`: Hex representation of the DID name data to be removed.
* **Behavior:** Removes an existing attribute from the DID.
* **Result:**
  * Verify the transaction in MetaMask or Remix.
  * Confirm EVM logs in the Remix terminal.
  * Ensure the attribute is removed on the Substrate side.

#### updateAttribute

* **Parameters:**
  * `did_account`: Public hex key (e.g., `0x…`).
  * `name`: Hex representation of the DID name data to be updated.
  * `value`: Hex representation of the new DID value data.
  * `validity_for`: Set to 0.
* **Behavior:** Updates an existing attribute of the DID.
* **Result:**
  * Verify the transaction in MetaMask or Remix.
  * Confirm EVM logs in the Remix terminal.
  * Ensure the attribute is updated on the Substrate side.

#### readAttribute

* **Parameters:**
  * `did_account`: Public hex key (e.g., `0x…`).
  * `name`: Hex representation of the DID name data to be read.
* **Behavior:** Reads the value of an existing DID attribute.
* **Result:**
  * Confirm the attribute information in the `readAttribute` field.
  * Data is displayed as a tuple (e.g., `tuple: xxxx`).

<br />

For more exhaustive definitions please look at the [DID Operations](/peaqchain/sdk-reference/javascript/did-operations) in the SDK.