Why Do We Need Security Screws?
The vast majority of fasteners have always been designed for widespread usability. The downside of universalised fastener drives is that screws can then be operated by any person with a readily-available screwdriver. It is not uncommon for fasteners to be installed in public places, playgrounds, or high-security areas, which has the potential to leave installations with unprotected fasteners vulnerable to vandalism or tampering. One solution to tamper prevention is to utilise a less common drive type, providing increased security at the cost of cross-compatibility.
Many of the very first developments to screw drives did not consider the benefits of exclusive screw drive designs, and generic drives were mass-produced with little thought given to security, at the time, developing an intentionally unwieldy screw drive would do little but exclude potential customers. The phillips drive, for instance, was marketed for its ability to operate most common screw sizes with only two sizes of screwdriver - a trait which now makes it widely unacceptable for use in public places.
That is not to say that tamper-prevention was not considered in early fasteners. Some of the first tamper-resistant drives appeared in the early 20th century, a design which can still be found today in one-way drives, which are essentially slotted drives, with removed head sections to prevent counter-clockwise rotation. The downside of this design is that they are slow to install, cannot handle high torque during installation, and cannot be easily removed, even by the intended operator. At the time, these rudimentary drives were simply all that was available - modern drives have seen significant improvements in tamper-proofing, without so severely sacrificing usability.
When first introduced, the Torx drive was considered to be uncommon enough to be suitable security feature in the prevention of tampering, but as Torx fasteners have become increasingly common for their many advantages, the accompanying drivers have become widely available, meaning that Torx drives are no longer considered to be adequate for most security applications.
Some tamper-resistant fastenings are simply created by rounding or completely removing the head of a fastener after installation, which makes the fastening almost impossible to remove. While this method is undeniably effective, it is not generally recommended, and a specialised fasteners will usually be available which provides effective security, without also rendering the screw unusable.
For many security drives, tamper-resistance can be achieved by the inclusion of a security pin, which immediately makes the fastener incompatible with standard tooling. For increased security, specially designed features such as snake eye drives may be required.
The main problem with security drives, and security features in general, is that they must continually evolve in order to prevent subversion. Custom-built, highly unique drives are constantly developed by companies to protect their products, but the cost of such designs is often prohibitive to most users. Despite this, generic security drives are often effective, and at the very least, serve as an inconvenience and a deterrent to most low-tech tampering.