Idea of Padlock Icon
This icon looks just like a padlock. The base of the lock is a square with slightly rounded edges. There is a circular shape in the center that looks just like where you would place a key. The hasp of the lock is on top and is simply a half circle tilted slightly to the left to indicate the lock is open.
This Padlock icon is made in Material Design style
developed by Google. This style is based on extremely simplified shapes, thin two-pixel lines, and is optimized for 24x24 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 6,100 icons, all in the same style and quality.