One way to hide an ex-officio agency of the United States Government was to label it truthfully --
The Society For Mystical And Metaphysical Research
.
In spite of the fact that the label was literally true, it sounded so crackpot that no one but a crackpot would bother to look into it. As a consequence, better than ninety per cent of the membership of the Society was composed of just such people. Only a few members of the "core" knew the organization's true function and purpose.
A classic Randall Garrett tale . . .