What is the meaning of the book "Hundred Characters of the War" in which the strategy is made in secret?

Jiexuan said: "A plan is made in secret, but it is defeated in leakage. The affairs of the three armies are more important than the secret. One person's business, not leaked to two people; tomorrow's behavior, not leaked to today. Detailed and push, careful not to send. He also said: to prevent the leakage of secrets in the speech; to be vigilant from the appearance of the leakage of secrets; but also beware of talking in their sleep and leakage of secrets ...... If some information can be said to some need to take advantage of the person, it may be advisable to tell a general, in order to show his trust, and to reveal these secrets is for better secrecy. This is a hidden secret in the public not secret so for secret important use between confidentiality principles. Speech leaks mainly because more words will be lost, should keep their mouths shut; appearance leaks mainly because of joy and anger in the color, should not show their feelings; reveal pleasantries mentioned the fear of leakage in the dream, at first glance seems to have this biased bizarre, not reasonable. But examine the ancient and modern Chinese and foreign use between the failure of the case, there are indeed many is leaking in the dream and the failure of the death. Prevent leakage in the dream method also invented for some spies, such as sleeping alone, prone to sleep, sleep with their heads covered, sleep with food in their mouths, and so on.