Laravel redirect back not passing variable - php

Question

I am creating a simple page to hash strings with md5, however the output is never returned.
This is the controller I use for these pages.
The function md5 is routed to the get and the function md5post is routed to the post.
The view has a form that is posted to the md5post function. it has one variable $input with the string to hash.
<?php
class ConversionsController extends \BaseController {
private $withmd5;
public function __construct(){
$this->withmd5 = [
'pagetitle' => 'MD5 hashing',
'description' => 'description',
'infoWindow' => 'info',
'btnSumbit' => Form::submit('Hash', ['class' => 'btn btn-default'])
];
}
public function md5(){
return View::make("layout.textareamaster")->with($this->withmd5);
}
public function md5post(){
if (strlen(Input::get("input")) > 0)
{
$hash = md5(Input::get("input"));
}
return Redirect::back()->withInput()->with("output", $hash);
}
}
And this is the view
{{ Form::open(['method' => 'post']) }}
<div class="row">
<div class="col-md-6">
<p class="well">
{{ Form::textarea('input', '', ['class' => 'form-control', 'rows' => 5]) }}
<span style="float:right;">
{{ $btnSubmit or Form::submit('Go', ['class' => 'btn btn-default']) }}
</span>
</p>
</div>
<div class="col-md-6">
<p class="well">
<textarea class="form-control" rows="5" readonly="true">{{ $output or "nothing" }}</textarea>
</p>
</div>
</div>
{{ Form::close() }}
When in my template file, the input is always displayed, however, the variable $output is always undefined. I have beent trying to use other variable names, but it wont work.
If I return the variable right before the redirect, I see the correct output.

Answer 1

I have found a solution.
In my view I had to use Session::get() to get the value.
That still didn't return the correct output, but I got it by casting this variable to string.
My solution:
{{ (string)Session::get('output') }}