Remember when you were told a secret in the playground and had to cross your heart and hope to die? The full version was 'cross my heart and hope to die, stick a needle in my eye'. It was mostly the thought of the needle in my eye which kept me from ever revealing that my mate Roger secretly loved Lucy Granger or whatever the secret was.
I have a few secrets at the moment which I have sworn not to tell though not with such a bloodthirsty oath as the playground version. My lips are sealed until such time as they are revealed by someone else.
Of course in time the need for secrets to be kept disappears. This can follow the death of a key person involved or simply the passing of sufficient time.
Some secrets are therefore eventually de-classified and revealed to the world. For instance, apparently, if we had ever captured Hitler, Winston Churchill was determined to have him executed in the electric chair - to hell with war crime trials.
Of course there are also secrets which are still shrouded in mystery, like the crashed UFO recovered at Roswell, New Mexico. The material which the craft was made from was listed simply as 'unknown' - spooky.
Can you keep a secret? Or are you a blabbermouth?