[array_key_first]

You can tell how safe a code snippet is from reading it.

Like, there's no way you're going to copy a 20 line algorithm from stack overflow on balancing a red-black tree and have it encrypt your harddrive.

Obviously you still need to test the code to make sure it works and understand what it's doing, but there is very little security risk here. Just look up the functions youre using and understand the code and you're fine.