diff --git a/README.md b/README.md
index c977df1..32f0845 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,7 @@ $parser->xml($payload);		    // XML > Array
 $parser->yaml($payload);		// YAML > Array
 $parser->querystr($payload);	// Query String > Array
 $parser->serialize($payload);	// Serialized Object > Array
+$parser->bson($payload);     	// BSON > Array
 ```
 
 #### Parse Input/Payload (PUT/POST)
@@ -109,6 +110,58 @@ $parser->only('id', 'name', 'email');   // Only return value from the selected k
 $parser->except('password');            // Don't return values from the selected keys.
 ```
 
+#### Mask function
+The mask function processes payload data using a configuration mask, thereby returning only a selected subset of the data.
+It works just like the `only` method but with the added benefit of allowing you to specify a mask in the form of an array,
+this means you can generate masks on-the-fly based on system and/or user defined conditions.
+
+##### Demo
+###### Mask
+Defining the mask, masks consist of basic array structure, for this particular example we have some rules for the data
+to be returned they include:
+    - the title of the post
+    - all the body's for all the comments.
+
+```php
+$mask = [
+    'post' => [
+        'title' => '*',
+        'comments' => [
+            'body' => '*'
+        ]
+    ]
+];
+```
+
+###### Sample Payload
+```json
+{
+    "post": {
+        "title": "Hello World",
+        "author": "John Smith",
+        "comments": [
+            {"body": "This is a comment", "date": "2015-02-20"},
+            {"body": "This is another comment", "date": "2015-05-09"}
+        ]
+    }
+}
+```
+
+###### Output
+This is the output generated as a result of applying the mask against the sample payload provided above.
+
+```php
+$output = [
+    'post' => [
+        'title' => 'Hello World',
+        'comments' => [
+            ['body' => 'This is a comment'],
+            ['body' => 'This is another comment']
+        ]
+    ]
+];
+```
+
 #### Wildcards/Special Keys (*, %, :first, :last, :index[0], :item[0])
 ```php
 $parser = new Parser();
diff --git a/src/Parser.php b/src/Parser.php
index 28eedcf..0b9a171 100644
--- a/src/Parser.php
+++ b/src/Parser.php
@@ -125,6 +125,37 @@ public function get($key = null, $default = null)
         return $default;
     }
 
+    /**
+     * Mask input data with a given mapping.
+     *
+     * @param array $mask
+     *
+     * @return array
+     */
+    public function mask(array $mask)
+    {
+        $keys = array();
+        foreach ($mask as $key => $value) {
+            $keys[] = $key . (is_array($value) ? $this->process_mask($value) : '');
+        }
+
+        return $this->only($keys);
+    }
+
+    /**
+     * Recursive processor for processing user masks.
+     *
+     * @param array $mask
+     *
+     * @return string
+     */
+    private function process_mask($mask)
+    {
+        foreach ($mask as $key => $value) {
+            return '.' . $key . (is_array($value) ? $this->process_item($value) : '');
+        }
+    }
+
     /**
      * Parse the HTTP payload data, autodetect format and return all data in array.
      *  Override the format by providing a content type.
diff --git a/tests/ParserTest.php b/tests/ParserTest.php
index 3fe1fe4..4c6a00b 100644
--- a/tests/ParserTest.php
+++ b/tests/ParserTest.php
@@ -15,6 +15,21 @@ protected function tearDown()
         m::close();
     }
 
+    /** @test */
+    public function mask_payload()
+    {
+        $parser = m::mock('Nathanmac\Utilities\Parser\Parser')
+            ->shouldDeferMissing()
+            ->shouldAllowMockingProtectedMethods();
+
+        $parser->shouldReceive('getPayload')
+            ->andReturn('{"message": {"title": "Hello World", "body": "Some message content"}, "comments": [{ "title": "hello", "message": "hello world"}, {"title": "world", "message": "hello world"}]}');
+
+        $this->assertEquals(array("message" => array("title" => "Hello World")), $parser->mask(array('message' => array('title' => '*'))));
+        $this->assertEquals(array("comments" => array(array("title" => "hello", "message" => "hello world"), array("title" => "world", "message" => "hello world"))), $parser->mask(array('comments' => '*')));
+        $this->assertEquals(array('posts' => null), $parser->mask(array('posts' => '*')));
+    }
+
     /** @test */
     public function wildcards_with_simple_structure_json()
     {