<\/span><\/h2>\nStandard screws use a “slot”, and a “standard” screwdriver has a blade that fits within that slot.\u00a0 Rotating the screwdriver applies torque to the outer edges of the screwdriver’s blade, which in turn, applies torque to the slot in the screw head, which turns the screw.\u00a0 You use the same tool to both fasten and unfasten the screw.<\/p>\n
Other common screw types are Phillips (“plus sign”), Allen (hex), and Torx (hex with wings).\u00a0 Square drive, often considered a “security” fastener, has a square aperture, and is becoming common, as well.<\/p>\n
![\"Screws\"](\"https:\/\/justinparrtech.com\/JustinParr-Tech\/wp-content\/uploads\/Screws-300x188.png\")
<\/p>\n
On the other hand, “security” bits have an odd number of lobes (three, five, or many), posts in the center, odd-shaped tips, and \/ or the like.<\/p>\n
![\"Security-Screws\"](\"https:\/\/justinparrtech.com\/JustinParr-Tech\/wp-content\/uploads\/Security-Screws-300x183.jpg\")
<\/p>\n
The concept behind security screws is that everyone<\/strong><\/span> has these two types of screwdrivers, and they are sold in every basic home or auto repair kit in the United States:<\/p>\n![\"StandardAndPhillipsScrewdrivers\"](\"https:\/\/justinparrtech.com\/JustinParr-Tech\/wp-content\/uploads\/StandardAndPhillipsScrewdrivers-300x300.jpg\")
<\/p>\n
Some<\/strong><\/span> people have these in their tool box, but not<\/strong><\/span> everyone:<\/p>\n![\"TorxAndHex\"](\"https:\/\/justinparrtech.com\/JustinParr-Tech\/wp-content\/uploads\/TorxAndHex-300x188.png\")
Very\u00a0few<\/strong><\/span> people have these:<\/p>\n![\"SquareDriver\"](\"https:\/\/justinparrtech.com\/JustinParr-Tech\/wp-content\/uploads\/SquareDriver-300x237.jpg\")
<\/p>\n
<\/p>\n
Almost no one<\/strong><\/span> has these:<\/p>\n![\"Security](\"https:\/\/justinparrtech.com\/JustinParr-Tech\/wp-content\/uploads\/security_bits-300x225.jpg\")
<\/p>\n
In other words, “Security Through Obscurity<\/strong><\/span>“.<\/p>\nThe first rule of security:\u00a0 “Security Through Obscurity” doesn’t work<\/strong><\/em>.<\/p>\n <\/p>\n
<\/p>\n
<\/span>Appropriate Uses for Security Fasteners<\/span><\/h2>\nThere are some absolutely appropriate uses for security screws (fasteners).<\/p>\n
In public areas, where theft could be an issue, it makes sense to use security fasteners to help prevent theft or malicious activity, as a casual deterrent — you wouldn’t want someone unbolting a public urinal, for example.<\/p>\n
In situations where safety is a concern, for example, in public transportation applications, it absolutely makes sense to use security fasteners, to help prevent malicious tampering.<\/p>\n
Even in consumer products, safety screws make sense to help prevent damage or injury, when placed next to a big yellow hazard label for any of the following:<\/p>\n
\n- Unusually sharp objects (such as a blade or needle)<\/li>\n
- Something spring-loaded, which when released, could cause injury.<\/li>\n
- Unusually delicate components (maybe use Torx, no need for a security screw)<\/li>\n
- Compartment containing poisonous substances or components<\/li>\n
- Compartment containing reactive or explosive substances or components<\/li>\n
- Compartment containing radioactive or radiation-emitting substances or components<\/li>\n<\/ul>\n
To put things in perspective, I use the words “help prevent”, because you can get a security bit set just like this for about $8<\/strong><\/span> at your local discount tool warehouse:<\/p>\n![\"Security](\"https:\/\/justinparrtech.com\/JustinParr-Tech\/wp-content\/uploads\/Security-Bit-Set-287x300.jpg\")
<\/p>\n
<\/p>\n
<\/p>\n
<\/span>Analysis of Security Fasteners<\/span><\/h2>\n<\/span>Legal<\/span><\/h3>\nThere is no law, requiring special licensing or qualification, nor restricting access to security bits.<\/p>\n
Therefore, anyone can obtain, manufacture, sell, transfer, own, or use them, even though few people actually have them.<\/p>\n
<\/span>Availability<\/span><\/h3>\nAs I mentioned above, security bit sets are widely available and inexpensive, thus making the lack<\/em> of having one, more of an inconvenience than a preventive measure.<\/p>\n<\/span>Knowledge \/ Skills<\/span><\/h3>\nNo special tools or knowledge is required to operate a security screwdriver, in order to remove a security screw.<\/p>\n
Security screwdrivers use the same paradigm as “normal” screwdrivers, familiar to a majority of the population.<\/p>\n
<\/span>Custom-Fashioned Tools<\/span><\/h3>\nPeople can visually inspect the fastener, and even develop their own tools.<\/p>\n
I once needed an extra-long S2 (square) bit — I ground down an extra-long standard (“slotted”) bit, that I purchased for about $0.80, and made it in to an S2 bit, rather than pay $15 for an extra-long S2 screwdriver or bit.<\/p>\n
My Physics teacher in high school took a large, slotted screwdriver, and ground a notch in to it, so that it would fit the “security” screw, holding the cover over the thermostat, so that he could adjust it whenever he wanted.<\/p>\n
Many “security” bits are versions of “normal” bits, but have a post in the center of the fastener.\u00a0 The tool for these can be constructed by starting with the “normal” tool, and using a drill press to bore a hole in the center of the tip.<\/p>\n
<\/span>Improvised Tools<\/span><\/h3>\nSome security fasteners use odd numbers of lobes (such as 3 or 5) or many lobes (similar to a gear).\u00a0 These can often be defeated using a precision-milled, slotted screwdriver, a set of which is also obtainable for about $6<\/strong><\/span> at your local tool warehouse.\u00a0 Although not perfect, there is usually one size of screwdriver whose blade can accurately span two or more slots on the fastener, and provide an adequate physical connection, in order to transfer enough torque, to un-screw the fastener.<\/p>\nCertain Allen and Torx bits are “somewhat interchangeable”, and both can usually be removed using an appropriate precision, slotted screwdriver.<\/p>\n
Fasteners with square or hex heads can probably be removed with a socket wrench, while cylindrical-headed screws might be able to be removed with clamping pliers.<\/p>\n
<\/span>Bypass<\/span><\/h3>\nLike all screws, security fasteners can be bypassed, either by cutting or damaging the material surrounding the fastener, or by drilling the screw head and using a screw extractor.<\/p>\n
In some situations (especially most public bathrooms!), the security fastener is connected to a component, which is then attached using standard bolts!\u00a0 The function of the security screw can be bypassed, simply by using a “standard” socket set or other tool to remove the “upstream” bolts or screws.<\/p>\n
Many “security” screws are versions of “normal” screws, but the fastener includes a post in the center of the slot within the screw head, and the corresponding tool has an aperture that fits around the post.\u00a0 Security versions of Phillips, Torx, Allen, and square drive screws can be bypassed by simply drilling the post out of the fastener itself, thus converting the screw to a standard type, that can be removed using the “standard” version of the tool.<\/p>\n
<\/span>One-Way Fasteners<\/span><\/h3>\nThere are many “one-way” fasteners that can be installed, but not easily removed.<\/p>\n
\n- Rivets<\/strong> – Rivets are installed by drilling a hole in two objects, and the rivet is inserted through the aligned holes between the two.\u00a0 A rivet tool then pulls on a pin inside the rivet, that is used to tighten, and then expand the opposite end, so that the two objects can’t be separated.\u00a0 Rivets must be drilled out, to be removed.<\/li>\n
- One-way Phillips<\/strong> – Like a Phillips, this fastener provides a suitable surface to apply torque, ONLY when rotating clockwise.\u00a0 In the counter-clockwise direction, there is no perpendicular surface, and therefore, no torque can be applied, and the fastener can’t easily be removed.<\/li>\n
- “Zip” Fasteners<\/strong> – Like a cross between a zip tie and a rivet, a plastic “nut” slips on to a ribbed post, in such a fashion that removal of the nut is prevented by blades that deform slightly against the direction of removal, effectively providing a one-way latching mechanism.<\/li>\n
- “Shear” or “Snap” screws<\/strong> – Fasten using a conventional tool, such as a Phillips or Torx.\u00a0 When a sufficient torque is applied, the bolt or screw head snaps off, resulting in a threaded rod that can’t easily be removed.<\/li>\n<\/ul>\n
All of these provide better security than security screws, but can be removed using a power drill and \/ or screw extractor.<\/p>\n
<\/span>Security<\/span><\/h3>\nAs stated, Security Through Obscurity<\/em> is not a valid security design.<\/p>\nThis is analogous to “Hiding the door rather than locking it”, which means that anyone who knows the location of the door, without authentication, can access the door.<\/p>\n
Anyone who buys a security bit set can remove a security fastener.<\/p>\n
Likewise, if authentication is required, there is a valid method to ensure physical access ONLY by authenticated users:\u00a0 It’s called a lock<\/strong>, which authenticates the user who uses the proper key<\/strong> to unlock it.<\/p>\nUnlike a security screw, which requires one of 10, or 20, or 30, or 300 different screwdriver tips, which can easily be determined by visual inspection, and subsequently obtained or manufactured (typically, inexpensively), a decent lock <\/strong>can’t be hacked through visual inspection, and presents one of 3,000 or more<\/strong> combinations (assuming 5^5 bitings vs. pin positions).\u00a0 A security lock might present one of 100,000 or more combinations.<\/p>\n<\/span>Conclusion of Analysis<\/span><\/h3>\nThe tools used to install or remove security fasteners are legal to own and manufacture, easy to obtain and use, and are inexpensive.<\/p>\n
Either a casual attacker (opportunist) or determined attacker can obtain the tools or possibly even bypass the fastener.\u00a0 A casual attacker might attempt to use standard tools to remove the fastener, and then opt for an easier target, while a determined attacker would simply be inconvenienced.\u00a0 Advanced knowledge of the target via reconnaissance and observation, would allow either type of attacker to obtain the appropriate tool in advance of an attack.<\/p>\n
Unlike a lock, neither the tool nor the fastener authenticate the user.\u00a0 Further, even security fasteners and their corresponding tools must conform to some standard which limits their variability, or else they would have almost no utility.\u00a0 Conversely, locks may be configured in one of thousands of possible combinations, and determining the specific configuration via visual inspection is precluded by the lock’s design.<\/p>\n
One-way fasteners are more tamper-resistant than security screws.<\/p>\n
Conclusion<\/strong>:\u00a0 Security screws are more of an inconvenience than a “security” measure, and will only deter some opportunistic attackers.<\/strong><\/p>\n <\/p>\n
<\/p>\n
<\/span>Rant:\u00a0 Security Screws Used in Consumer Products<\/span><\/h2>\n<RANT><\/strong><\/span><\/p>\nNow that we understand the nature of, and utter uselessness of security screws, let’s take a minute to think about those times, when, while attempting to fix something, you stumble across a tri-wing screw, or one of those “Torx security” screws with the post in the center.<\/span><\/p>\nWhat problem was the manufacturer trying to solve?<\/span><\/p>\nOutside of a safety concern (public safety, sharp, spring-loaded, poisonous, radioactive, or reactive) accompanied by a big, yellow hazard sticker, WHY<\/strong> would the manufacturer use a security screw?<\/span><\/p>\nHere are some possible reasons, all bad<\/strong>:<\/span><\/p>\n\n- Prevent unqualified access<\/strong>.\u00a0 NOPE.\u00a0 I can buy any bit on the internet for a couple of dollars, whether I’m qualified or not.<\/span><\/li>\n
- Delicate parts inside<\/strong>.\u00a0 Yes, we know.\u00a0 Using a STANDARD, but lesser used bit, such as Torx, is a great way to signal someone that “precision is involved, proceed carefully”, without pissing them off.<\/span><\/li>\n
- Fastener is more precise.<\/strong>\u00a0 NOPE.\u00a0 Nothing is more precise than Torx.\u00a0 Explain to me, how a pentalobe or tri-wing fastener is somehow more precise than Torx, which provides a positive friction lock between the tool and fastener, and delivers plenty of surface area to disperse torque evenly.<\/span><\/li>\n<\/ul>\n
The real message to the consumer is:\u00a0 “You’re good enough to buy this, but way too stupid \/ unqualified to fix it<\/strong><\/em>“.<\/span><\/p>\nThere is NO VALID REASON TO PUT SECURITY SCREWS IN CONSUMER PRODUCTS.<\/strong><\/span><\/p>\n<\/RANT><\/strong><\/span><\/p>\n <\/p>\n
<\/p>\n
<\/span>“Standard” Screw Fasteners are Problematic<\/span><\/h2>\nThe screw thread<\/em><\/strong> (or worm drive) has been around since Roman times, used in presses and water pumps.<\/p>\nAs a mechanical fastener, screws<\/strong><\/em> have been in use since the mid-1400’s, and came in to popular use in the late 1700’s, once mass-production techniques made them widely available.<\/p>\nThe concept and design of a worm-drive fastener with a single slot in the top, used to provide torque between the tool (screwdriver) and fastener, remained largely unchanged for over 400 years<\/strong>, until Phillips introduced the Phillips fastener and corresponding Phillips screwdriver in the 1930’s<\/strong>.<\/p>\nThat isn’t to say that “standard” screws were standard — other than the “screwdriver” tool itself, there were very few “standard” sizes, diameters, thread spacings, thread depths, nor taper dimensions.<\/p>\n
<\/span>The Two Most Common Screw Types Are Inferior<\/span><\/h3>\nAlthough standardization in the mid-1900’s helped with fastener compatibility between multiple applications, this didn’t change some of the core flaws of the “standard” slotted screw<\/strong>:<\/p>\n\n- Only two possible tool alignments, oriented 180 degrees apart, makes it difficult to position the tool quickly and accurately within the slot of the screwdriver.<\/li>\n
- The tool does not self-center within the slot, making it likely that the tool will slip off-center, or even slip out all together.<\/li>\n
- The tool only transfers torque to the fastener along half of each face of the tool’s blade, making “cam-out” (when the tool slips out of the slot) and\/or damage to the slot more likely, as torque increases.<\/li>\n
- As with most screws, the fastener can’t be placed on the tool and subsequently set — it must be placed on the material and started from there.<\/li>\n
- The screw absolutely requires a pilot hole.<\/li>\n<\/ul>\n
Invented in the 1930’s, the Phillips screw and screwdriver<\/strong>, still in common use today, was designed to overcome many of the shortcomings of the standard, slotted screw:<\/p>\n