Need to Know
The phrase need to know is use to describe information that is only given based on what a person needs in order to do their job and nothing further. It is a method of maintaining confidential information.
Our mission was too critical to fail. The legislation had to pass. The entire plan hinged on secrecy so everyone outside of the inner circle was operating on a need-to-know basis in the hopes that compartmentalizing our activities would prevent anyone from being able to piece the entire thing together and leak the information.