Is a Muslim obligated to reveal the secrets of his profession that distinguish him from others, or is it permissible for him to conceal them to preserve his standing?

Many scholars have concluded that it is obligatory for the fundamental crafts to be available in Muslim lands, and that specializing in certain crafts becomes a communal obligation (fard kifayah) if Muslims are in need of them. If those skilled in these crafts refuse to fulfill this obligation, the Imam should compel them to do so. Since establishing industries is a communal obligation, providing skilled professionals to work in these industries is also an obligation, similar to the obligation of a guardian to hand over a minor to someone who will teach him a craft. Accordingly, the ruling on someone who asks you to teach him your craft varies depending on their situation. If Muslims are in need of him learning this craft, and there is no one else to teach him but you, then it is obligatory for you to respond to his request. However, if there is no such need, then you are not obliged to teach him.