cloak (someone or something) in secrecy
To hide someone or something from another person or from public view. The residents complained that the board cloaked its decision process in secrecy, not allowing anyone to see the final plan.
swear (one) to secrecy
To make one promise that they won't reveal something that they know about. The company swore me to secrecy before promoting me to work on their latest product. OK, I'll tell you, but I have to swear you to secrecy!
cloak someone or something in secrecy
Fig. to hide or conceal someone or something in secrecy. Patrick cloaked his activities in secrecy. The agents cloaked the spy in secrecy, making her identity a mystery.
swear somebody to ˈsecrecy
make somebody promise not to tell a secret: Before telling her what happened, I had sworn her to secrecy.Everyone was sworn to secrecy about what had happened.