It was narrated that 'Ali said:
"The Messenger of Allah said: 'The screen between the Jinn and the nakedness of the sons of Adam is that when a person enters the Kanif, he should say: Bismillah (in the name of Allah).'" (FR)
English reference (FR): Vol. 1, Book 1, Hadith 297 (FR)
Arabic reference (FR): Book 1, Hadith 314 (FR)