What is secrecy, and why and how it should be kept ? These three questions determine the structure of this article : the notion of “metaphysical secrecy” is about the object of secrecy and the sections on “initiatory” and “political” secrecy contain an overview of the reasons and techniques of secret-keeping in Islam. This analysis is followed by a synthesis based on the theory and techniques of secrecy in the texts of the Hurufi messianic movement, founded in Iran in the second half of the 14th century.