"Due process of law"

What is meant when someone says "due process of law"? What due process rights were covered in the case of "Brown v. Mississippi"? "Powell v. Alabama"? Create a sho​‌‍‍‍‌‍‍‌‍‌‌‍‍‍‌‍‌‌‌‍​rt summary of both cases and address anything you would have done differently.