Think about it like this, if there was a new life form [that came in peace] that touched earth and only the government knows, why should they tell us? We do have the right to know, but the question really is, should we? Why disturb the way of life we have now?
The government can stop bad stuff(violence, language) from being released to the public. This will help to protect everyone especially the younger people. Also the government can keep confidential missions/operations secret until after they are completed(the mission to kill Osama bin Laden) and no one wants him to be back.
Education and awareness of the public is required if we are going to consider ourselves a democracy. I do understand that there are special circumstances where national security is put at risk but I also feel that the goverment sometimes uses that as an excuse to restrict information that could be damaging to their caimpaign instead of national security.
The best way to control any society is through the media. I would never willingly give away my access to information for any reason. It is much better to know what is going on around you then to live a life of ignorance. Besides peace is much to subjective a word. New info could include a new law that not everyone will agree with so they don't release it to the public, or technology that is morally questionable, so it isn't announced to the public. Such a law would be much to gray for my tastes.
When ever the government says it's worried about national security or disturbing peace later it always turns out they used it for political purposes. The government can't be trusted with this. It's better for information to be free. The Founding Fathers were right about that. First amendment! We shouldn't trust the government to interfere with this.
If the government was controlling the entire flow of information and innovation, it would only promote skepticism. The public already views politicians as generally manipulative; if this idea were to be put in place, it would simply be backing up this viewpoint with policy. It would open the door to greater corruption by providing those in charge with lawful means of covering their tracks and stifling opposition.
For instance, it could be used to stifle discoveries and scientific progress. It's definitely not a good idea, because the government would be able to screen all information before releasing it, and since knowledge is power, the government would have all the power. The people would have none. Absolutely none.