I remember when my father taught my brother and sister and I the magic of invisible ink. We wrote a message on a piece of paper in lemon juice, and let it dry. A short time afterwards, he held a match under it, just far enough away so that the paper didn't catch on fire. The heat from the flame caused the letters to show back up. I don't remember thinking of this as anything more than a curiosity, and never used the method to transmit intelligence reports to anyone. I guess the subtlety of espionage was lost upon us. Playing cowboys and indians, and little league baseball was more fun.
The James Madison Project (JMP) tried to discover the formula for invisible ink that was used by the intelligence offices of the United States almost 100 years ago. It looks like the greatest way to make invisible ink remain invisble is to hide it away where no one can read it. Chances are good that the method used is nothing greater than that home science experiment that I referred to above.
The JMP is a nonprofit organization based in Washington, D.C., and created in 1998. Their mission is:
to promote government accountability and the reduction of secrecy, as well as to educate the public on issues relating to intelligence and national security through means of research, advocacy and the dissemination of information.One of their earliest efforts was to try to identify the oldest documents that exist which are classified as "Top Secret" by the United States Government, and they filed a Freedom of Information Act (FOIA) request to do so. They received a response from the National Archives and Records Administration identifying the titles of the six oldest documents on record, all of which have to do with secret inks for invisble writing.
The JMP followed up their FOIA with a request that the documents be declassified. They weren't so much interested in the secret to invisible ink as much as they were in trying to get the goverment to stop protecting documents that probably no longer contain secrets worth protecting. Their request was rejected by the Agency, and they filed a complaint in Federal Court in an attempt to have the denial overturned. The Court made it's ruling this February. It appears that the secret to invisible ink will remain a secret.
During the exchange of documents filed in the case, the JMP's memorandum of law in opposition to a motion for summary judgment contains some great material regarding some of the information that our government has protected in the past, and an excellent history of the use of invisible inks. Some of the documents which they point to as having been held secretly:
- The U.S. Army classifying a study on archery under the heading "silent, flashless weapons." David Wise THE POLITICS OF LYING 67 (Random House, 1973)("Politics of Lying").
- The U.S. Navy classifying a report on sharks that was derived entirely from publicly available sources, purportedly to keep the documents from falling into the possession of the Soviet Navy, but more likely to keep the information from discouraging recruitment. Id. at 67-68.
- The Joint Chief's classifying as "TOP SECRET" a report which criticized the gross abuses of secrecy classification at all levels in the military. SANFORD J. UNGAR, THE PAPERS & THE PAPERS 219 (Columbia Univ. Press/Morning side ed., 1989).
- The Pentagon adamantly refusing to publish information that acknowledged that NASA had sent monkeys into space, despite the fact that the Washington Zoo had already identified its monkeys with a plaque praising their participation in rocket experiments in the U.S. space program. The Washington Post reported that the Pentagon explained it was trying to preserve the U.S. relationship with India, where certain obscure sects still practiced "monkey worship." Politics of Lying, at 67-68.
- The classifying of White House menus as "Top Secret." Id. at 70.
- Weather reports produced by an aid to General Eisenhower during World War Two still being classified even thirty years after the fact. Commission Report, at 52.
The memorandum also gives a description of the uses of invisible inks by the ancient greeks, by both sides during the American Revolutionary War, and by spies during World Wars I and II. It also cites the wide spread dissemination of formulas for hidden inks by books and through the internet, and gives examples of different types, including: Israeli Pale Blue Secret Ink No. 2, Gestapo Blood-Red Secret Ink, and Australian Secret Vapor Ink. JMP insists in their memorandum that the secrets of over 80 years ago regarding invisible inks are likely no longer secret anymore.
Should the government protect secrets that are probably not still secret? Is national security threatened by the release of these documents? The Judge in this case issued his decision without actually reviewing the documents in question, on the basis of a statement from the CIA that disclosure of the technology involved could affect national security. I hope that isn't true. I'd like to think that our intelligence agents are using methods a little more sophisticated than something I learned as a child.