Embedded systems using core soc silicon from a number of manufacturers have started to use what is known as 'secure boot'. This is typically the case in applications which utilise conditional access system software to protect content. The emphasis on using secure boot is largely driven by the conditional access industry itself.
The principal purpose of these products is to restrict the public's freedom. So it is natural that their means involve restricting our freedom too.
In DefectiveByDesign.org we organize protests against such devices. They don't deserve help.
In this context, I believe both terms are interchangeable and effectively mean the same thing. It is secure because only authenticated code is allowed to be executed, thus another step to avoid piracy,
If that is meant to refer to sharing of copies of published works, please don't call that "piracy". That is a propaganda term which is used to spread the assumption that sharing is bad. See http://www.gnu.org/philosophy/words-to-avoid.html.