phylo_roadking wrote:It would make sense that code breaking and its methods are so sensitive issues that secrecy even 70 years later may feel justified. At least if you're a government official.
And of course preserve the reputation of a beloved father of the nation like FDR who might have given the orders to spy on an ally...
Or the other way around with Churchill being the benefactor of the information.
The source rather than the informaton itself giving reason for classification could be as simple as the angle of a photograph showing, in the cases of photos I dealt with in the early 80s, Soviet armor on training exercises. The classification was given to protect the individual who took the photo. Given the angles and locations it would have been quite easy for the KGB or Stasi to learn the location of the photographer and arrest him for providing information.