The project was cloaked/shrouded in 'secrecy'. [=the true nature of the project was kept secret]
She 'swore him to secrecy'. [=made him promise to keep a secret]
(..) Then I assume you have the location. Confirmed by all. Independently. I had feared the Priory's penchant for secrecy might prevail. The prospect of death is strong motivation. It is here. In Paris, Teacher. It hides beneath the Rose (..)2006 The Da Vinci Code