It is an emblem or a shield with the letters SSL inside of it right in the middle of the shield. There are four total points on the shield, one at the bottom, two on the top left and top right corner and then one rounded point slightly above the two corners.
Related to Security SSL Icon
Related icons are the icons with matching tags, as well as all security icons. All icons are in the same flat style. You can either download free PNG icons or buy SVG vectors