WASHINGTON -- Diagrams of nuclear weapons are available to anyone with access to the Internet, and earlier this month the United States government published an accounting of every bit of bomb fuel it ever made, and where it all went, down to nearly the last ounce.
The Energy Department even has an Internet web page where people hungry for nuclear secrets can search through abstracts of once-classified documents and learn how to order the full documents for free.
If they are brief enough, the government will fax the documents out.
So what's left for the bomb-makers to keep secret?
Plenty, they say, and the secrets may be more important now than in the days when "nuclear threat" meant Communist bombs.
Then, the object of the classification system was mostly to keep the Russians and the Chinese from learning the extent of American nuclear strength and from picking up American techniques for turning their uranium and plutonium into more efficient weapons.
But now, officials say, the problem is to keep Third World countries and even smaller entities from learning to build any weapons at all.
With increased commerce in plutonium around the world, and surpluses of nuclear material from the former Soviet Union, the issue is no longer the efficiency of weapons.
Whether a Third World nation or a terrorist group is building an efficient bomb or a bomb of obsolete design -- one that yields fewer kilotons of TNT equivalent per kilo of uranium or plutonium -- does not matter.
The point is to keep any nuclear weapon, of whatever quality, from being built.
For years the Atomic Energy Commission, and now the Energ Department, operated on a principle used nowhere else in the American government: that whole categories of ideas are "classified at birth," secret until proven otherwise.
Now, with the new emphasis on openness, there is a lot of catching up to do in declassification.
Is it worth it? The Energy Department spends $9 million a year now on declassification decisions, and in the midst of budget cutbacks for environmental cleanup, it is not eager to spend more.
There may be other reasons for resistance to opening up the vaults.
Many critics of declassification are the people who know what secrets are kept and whose livelihood has been tied up in keeping those secrets.
Now, in an era of layoffs, their desire to hold onto a job may, in part, be driving their desire to hold onto nuclear information.
"This whole classification discussion has been much more an argument about job security than national security," said Charles R. Hansen, a specialist in nuclear bombs. Some of the decisions about classification are being made, he said, by people who would become less important if the system ceased to exist.
The Energy Department has always been slow to answer questions about nuclear weapons, but that is changing.
Recently the department boasted that it had finally cleared away all the requests made in the 1980s under the Freedom of Information Act and three-quarters of those made from 1990 to 1992.
It promised to finish with the requests from 1993 and 1994 by 1997. According to the department, 1995 was the first year that it had closed more cases -- by releasing information or refusing to release it -- than the public had filed.
There are some facts that the Energy Department still won't talk about. No one knows whether these are real secrets or information that ordinary people already know. Even in an era of openness, there can be value in ambiguity and mystery.