# partcp-php

Library for leveraging the ParTCP protocol in PHP projects


## Requirements

- PHP 8+
- php-sodium extension
- YAML library (tested with [Symfony YAML component](https://github.com/symfony/yaml))


## Usage

You have to make sure that a YAML library is loaded and the yaml_emit() and
yaml_parse() functions are available. The following code shows how this can be
achieved when using the [Symfony YAML component](https://github.com/symfony/yaml)
(without the Symfony framework):

```php
if ( ! function_exists('yaml_parse') ){
   require_once 'yaml/Exception/ExceptionInterface.php';
   require_once 'yaml/Exception/RuntimeException.php';
   require_once 'yaml/Exception/ParseException.php';
   require_once 'yaml/Dumper.php';
   require_once 'yaml/Escaper.php';
   require_once 'yaml/Inline.php';
   require_once 'yaml/Parser.php';
   require_once 'yaml/Unescaper.php';
   require_once 'yaml/Yaml.php';
   
   function yaml_parse( $string ){
      return Symfony\Component\Yaml\Yaml::parse( $string );
   }
   
   function yaml_emit( $string ){
      $option = Symfony\Component\Yaml\Yaml::DUMP_MULTI_LINE_LITERAL_BLOCK
         | Symfony\Component\Yaml\Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE;
      return Symfony\Component\Yaml\Yaml::dump( $string, 3, 2, $option );
   }
}
```

Load the ParTCP PHP class files:

```php
require_once 'crypto.class.php';
require_once 'key_storage.class.php';
require_once 'identity.class.php';
require_once 'incoming_message.class.php';
require_once 'outgoing_message.class.php';
```

Set the base directory for storing identities:

```php
ParTCP_Key_Storage::$storageDir = '/path/to/writable/directory';
```

Or, if you have your own class for storing keys, register it with the
ParTCP_Identity class:

```php
ParTCP_Identity::$storage = 'My_Own_Key_Storage';
```

Create a private (local) identity and submit the public key to
a remote server:

```php
$localId = new ParTCP_Private_Identity( 'name@server.tld', TRUE, TRUE );
$remoteId = new ParTCP_Public_Identity( 'server.tld', TRUE );
$msg = new ParTCP_Outgoing_Message( $remoteId, $localId, [
   'Message-Type' => 'key-submission',
   'Credential~~' => $credential,
   'Public-Key' => $localId->pubKey,
]);
$msg->set_date();
$response = $msg->send();
```

Check the response:

```php
if ( $response['status'] != 200 ){
   die('Could not connect to server');
}

$msg = new ParTCP_Incoming_Message( $response['body'] );
if ( $msg->get('Message-Type') == 'Rejection-Notice' ){
   die( 'Key submission rejected: ' . $msg->get('Rejection-Reason') );
}

$result = $msg->get_signature_status();
if ( ! $result ){
   die( 'Signature error: ' . $msg->signatureStatusMessage );
}
```

Use low-level crypto functions:

```php
ParTCP_Crypto::set_remote_pubkey( $pubKey );
ParTCP_Crypto::set_local_privkey( $privKey );

$signature = ParTCP_Crypto::generate_signature( $data );
$verified = ParTCP_Crypto::verify_signature( $signature );

$encrypted = ParTCP_Crypto::encrypt( $data );
$decrypted = ParTCP_Crypto::decrypt( $encrypted );
```