private - nested classes php or other method

I am looking for a method like the suggested php >=5.6 nested classes.

example

class Parent {

   public function call(){
       return new $this->Child;
   }

    class Child {

    }

}
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Basically what I'm looking to do is something like

Secure::Encryption::Get();
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or

Secure::Encryption($type)::Get();
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You can do something similar in JavaScript ex:

function Secure(){

     return {
   Encryption: function(){
             return:{
                 Get:function(){}
             }
        }
     }
}
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I want to have private members only accesible to theEncryption member. I know that nested classes are not possible yet so I'm looking for an alternative