# Private layer

## Event chain

### **Create a new event chain**

```php
$chain = $account->createEventChain(); // Creates an empty event chain with a valid id and last hash
```

*Note: You need to add an identity as the first event on the chain. This is **not** done automatically.*

### **Create and sign an event and add it to an existing event chain**

```php
$body = [
  '$schema' => "http://specs.example.com/message#",
  'content' => "Hello world!"
];

$chainId = "JEKNVnkbo3jqSHT8tfiAKK4tQTFK7jbx8t18wEEnygya";
$chainLastHash = "3yMApqCuCjXDWPrbjfR5mjCPTHqFG8Pux1TxQrEM35jj";

$chain = new LTO\EventChain($chainId, $chainLastHash);

$chain->add(new Event($body))->signWith($account);
```

You need the chain id and the hash of the last event to use an existing chain.


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