Double blind

Just a question: Would anyone know some definitive source, or pointers, to discussions either formal or informal, on the logic behind double secrets i.e. situations where it is a secret that some secret exists ..?

Yerah, it’s relevant in particular now that some countries’ government seems to have failed to keep that double secret completely, but should be more systematically dealt with, I think, also re regular business-to-business (and -to-consumer) interactions.

So, if you have some neat write-ups of formal logic systems approaches, I’d be grateful. TIA!