Cron job with shared hosting CPanel
You may want to try creating a wgetrc file that contains all your values.  Check the man page for wget as a reference.. Here's a wgetrc of mine:

post-data=name=civicron&amp;pass=&lt;password&gt;&amp;key=&lt;sitekey&gt;
output_document = -
quiet=on
timeout=1


Also - check your Apache/nginx logs for the actual URL that was requested that corresponds to a wget that resulted in a "You need to send a valid key" error.  Maybe something is getting truncated; the web server log can help determine this.