the Messenger of Allah said: "The screen between the eyes of the jinns and nakedness of the children of Adam when one of you enters the area of relieving oneself is saying: 'Bismillah.'"  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ سَتْرُ مَا بَيْنَ أَعْيُنِ الْجِنِّ وَعَوْرَاتِ بَنِي آدَمَ إِذَا دَخَلَ أَحَدُهُمُ الْخَلاَءَ أَنْ يَقُولَ بِسْمِ اللَّهِ