Hi, every time I go on Minecraft it says SecurityCraft is not a valid mod file please can you Help.

You are trying to run a version of SecurityCraft that is not made for the Minecraft version you're using. The number in the square brackets ([]) at the start of SecurityCraft's file name tell you what Minecraft version that file is made for. If they do not match up with the Minecraft version that you want to play on, download the correct file from the CurseForge page.