Explain the secretly signed cybersecurity directive, Presidential Policy Directive 20, which didn't go through congress.

It has been reported that President Obama signed Presidential Policy Directive 20, giving the military power to act more aggressively to thwart cyberthreats. Congress has repeatedly defeated bills like the Cybersecurity Act. Why has congress been bypassed and what does this directive have in common with the bills that have been shot down in congress? How can the people feel confident in the constitutionality of something so controversial that isn't publicized? How is the Pentagon left with the power to "fill in the blanks"? We feel this act could threaten our internet freedom, the sovereignty of other nations, international legal issues, etc. Thank you.