Which Padlocks Are Most Secure: Unbreakable

Which Padlocks Are Most Secure

Every lock can fail. Given sufficient tools, time, and motivation, a master locksmith can open most, and enough pressure will eventually break the rest. Even diamonds break. However, the average thief isn’t prepared for heavy duty, (mostly) theft-proof locks. Though an angry spouse or a paid PI is more persistent than the average pilferer, they probably aren’t ready to cut boron alloy or face a lock with no visible shackle at all.

More or Less

There are a small handful of locks (not padlocks) that have never been picked, but they are incredibly unique. Furthermore, they’re not portable. Doubtless, some crafty thief or locksmith will figure them out in time.


When it comes to security, most people are still using basic locks. You can even stop a locksmith if you don’t have a keyhole for them to pick. Thieves aren’t usually looking for the hardest lock to pick. If you’re trying to steal something, you want to be able to get in and out quickly and quietly.


Your nosy spouse probably doesn’t want to get caught in the act. No matter how crazy their behavior, that’s going too far for most people. Risking arrest is rarely ‘worth it.’

What’s in a Name

Some things have perfectly recorded histories. You can discover their history and where their names originated. Not so with padlocks. In fact, the number of possibilities for where the name came from is more substantial than most words.


The name of a thing is usually a clue about its origins or its creator, but “padlock,” is unique. It may be one of the most challenging words to trace back through time accurately.

The Earliest Padlocks

The Egyptians and Chinese had something similar to a padlock as early as 1000 BC. While the Chinese models flourished, the Egyptian versions never really caught on outside of the area.

Due to changes in politics and trade routes, these are not the direct ancestors of your locks today. Despite the differences, they are still padlocks. Resultantly, the modern version you know has more in common with the early Roman models circa 500 BCE. It is possible some crafty traveler stole the idea from further afield, but the exact origins are shrouded in mystery.

Roman “First” Padlocks

The first padlocks were simple, utilizing a shackle that was directly manipulated by the key. This is known as an integrated mechanism. As pioneering technology goes, it’s a brilliant leap of logic, and a great way to secure your stuff.

Merchants and Royals were the first to be able to afford these personal locks. Unfortunately, early models were easy to pick, like those tiny, cheap diary locks you can open in a second with a bent piece of wire.

Later locks included the famous Scandinavian cast heart locks, so named for their shape. Riveted locks were accessible and inexpensive for decades but eventually went out of style. Unfortunately, the rivets holding the body together weren’t as efficient or breakage proof as solid bodied die-cast locks that came later. Riveted locks fell out of style almost as soon as solid body locks became affordable.

The Many Possible Roots

Undoubtedly these early locks were not called “padlocks,” but the name had to come along somewhere. There are several sensible and popular theories about where the name came from.

  • Christopher Pohlem In the 19th century, a Scandinavian inventor created a new style of padlock that was more effective. Though it’s a stretch, The Pohlem Lock could also be an early iteration. Misheard words change in the repetition. After decades of being repeated, much like the ‘telephone game,’ we played as children, “Pohelm Lock,” could become the modern “padlock.”
  • Pad- There are three reasons why this may be the origin. First, to pad, or to walk night be at the root of a padlock’s name because the lock itself can be removed and walked to a new location. Second, it may refer to guarding a path. Third and finally, a pad may also be a reference to an old name for a gate. Since a gateway is an ideal location for a padlock, this makes a lot of sense.
  • Paddock- A paddock is an enclosure for animals. Vikings from an English settlement in York are credited with coining the term.
  • Pannier- Saddlebags and baskets used on animals (and more recently on bicycles and motorcycles) are called panniers, also known as pads. Locking up valuables in these portable containers might have contributed the name.

What Makes a Padlock: Parts

A padlock is essentially any portable lock. Thus, the ability to take your lock with you to protect things in different locations is the essence of what a padlock is and what it does.

No matter what it looks like inside or out, all removable locks that are reusable are in the padlock family. You will find them as small as an earring for novelty, and large enough to secure a hangar bay door. However, there are numerous ways to configure the ‘guts’ of your padlock, so don’t be confused.

All Padlocks

Common ancestry means every padlock has the same three essential components. Simple or complicated, and regardless of how you open them, some things don’t change. Just as all padlocks can be removed, they all have these parts:

  • Body- The outside of the lock that encases the mechanism and holds the shank in place. The most common shapes are square and rectangular cuboids, or the ‘disk,’ rounded shape.
  • Locking Mechanism- The components inside allow the shackle to hold securely in place, locking or unlocking. These come in many varieties. The most well known are the dial or combination locks, and those with traditional keys. However, you can get digital locks, or use fingerprints, and even magnetic opening locks.
  • Shackle or Shank- The piece of metal that loops through a latch to hold something shut. There’s not much to this piece. It can rotate or click into place when pressed down. The shackle can have a divot cut out on at least one side to allow an internal part of the locking mechanism to slide into and hold it in place.

Integrated & Modular

An assembled integrated padlock is functionally all one part. You can’t remove the shackle without breaking the lock apart. Modern locks are mostly modular. The more recent locks use “locking dogs,” which can often be small ball bearings. These slide into place in the divots or ‘cuts’ in the shackle to hold it still.

Picking a Padlock

Choosing the best padlock can be difficult, but sometimes the best way to know what makes a quality product is to understand how to break it. There are several ways to get into a padlock. Some are sneaky and leave little to no trace. Meanwhile, others just demolish the lock.

Break-in Tools

  • Lockpicks- Typically, these sets have a torsion wrench and many picks with different shapes on the ends. You usually need several picks for one lock. Plus the more complicated it is, the more picks are likely to be needed.
  • Shims- A shim is made of slender, malleable metal, like the sides of a soda can. You slide it down the shank of a lock, so it disengages the locking mechanism.
  • Boltcutters- You can use these industrial strength cutters for more than bolts. Many locks have shackles that are vulnerable to this type of attack.
  • Saws- If you’re thinking of the type of saw used to cut trees, you have the wrong idea. That would be very difficult to use on such a small item. A jewelers saw, on the other hand, is designed to slice through small pieces of metal.
  • Dremels- A Dremel tool has attachments made to cut as well as grind and polish. A diamond cutting bit would get through most shanks.
  • Drills- Sometimes just drilling into the center of a lock will compromise the mechanism.
  • Hammers- Not all locks are susceptible to percussion. Regrettably, many cheap locks open if you tap them until the mechanism falls into place. Sadly, others break into pieces.
  • Crowbars- Some locks pop open or break apart with judicious application of leverage. Crowbars can be used to put pressure on both sides of a shackle simultaneously. That much force can break steel.
  • Wrenches- A pair of wrenches can be used to push outward on a standard shackle to drop the locking dogs out of place, or break a lock made of softer materials.
  • Liquid Nitrogen- This is overly complicated, not to mention dangerous, but you can break most locks by pouring liquid nitrogen on them and smashing them.

Placement Matters

Make certain you’re matching your lock to your container. A cunning thief will take any opportunity, and may not try to get in through the lock at all. Naturally, any security measure is only as good as its weakest point.

Just as a high-security steel door can be stronger than the walls or windows around it, you always need to consider what you put your lock on. Simply put, sometimes it’s easier to break the container. There’s little point in placing the best lock in the world on a cardboard box.

Top 5 Best Secure Padlocks

This carefully curated list of exceptional locks to help you find the very best. When it comes to personal privacy, it’s worth the time and a little extra expense to make sure your information or items don’t fall into the hands of thieves, stalkers, psycho exes or angry cheating spouses.

For the purpose of this list, I’m assuming you don’t intend to secure a bunker or airplane hangar. These padlocks are more suited to everyday needs. You should be able to lock a trunk, locker, or fence with them as long as your latch has a hole of sufficient diameter.

1. Mul-T-Lock MT5+ #13 C-Series Padlock

When it comes to the top of the line near-unbreakable locks, the Mul-T-Lock is first on our list. You’d be hard pressed to find a sturdier option.  The Mul-T-Lock® unique high precision ten telescopic pin tumbler system is indeed next level when it comes to padlock security. Plus there’s an impressive list of other safety features.

Everything You Need and More

To begin with, this lock has a UL437 cylinder which meets CEN & ISI standards. Additionally, the core is black plated solid brass with a protective shutter to keep out dust and debris. Having a shutter to keep out debris helps protect the life of your lock and prevents natural jamming from common conditions like dust and problems like small insects. 

What that means to you is that your lock is pick, bump and drill resistant. The dual-sided, unique-to-each-lock keys come from the MT5+ Key Control System, which is patented. Each key has an ergonomic top and opens at 55˚-65˚key rotation. As long as you have the right key, the lock will open easily and smoothly, with minimal effort.

There are three active locking mechanisms. A key impression might get a thief a key that fits inside your lock, but it still won’t open because the tip of each key features an interactive spring. This feature, the Alpha Spring, opens a unique rear pin but that’s not all. Doing this creates a third sheer line plus.

… And More

The #13 C-Series Padlock comes with a limited lifetime mechanical warranty. Moreover, the hardened boron alloy shackle comes with a protector to keep it from being cut. 

Not only will thieves be thwarted in reaching the shackle, but the metal is also ridiculously durable. The amount of time and effort it would take to break into this lock is prohibitive all on its own. 

Drainage holes help keep this lock from freezing. It’s an excellent choice for extreme weather. Essentially, Mul-t-lock thought of everything, but then kept going. A #13 C-Series Padlock will surprise you with its value. You can never be too safe. 


  • The list of security features speaks for itself here.
  • Even if someone could manage to open your #13 C-Series Padlock, they couldn’t hide it since you need a key to close it again.
  • With a 30-day refund or replacement guarantee from the manufacturer, you have time to see it in action for yourself.


  • First, if you lose your Magnetic Key Cutting ID Card, you can’t get a new key made. Locksmiths and other key-makers, can’t legally replicate “do not duplicate” keys. Without permission from the proven owner, they can lose a license or get a hefty fine. Since this card is your proof, it’s imperative to keep it secured. Fortunately, this is a bonus as well as a caution.
  • Second, you will have a tough time getting this lock off of anything if you lose your keys. The boron hardened shackle and body is no joke. Realistically, wurtzite boron nitride (w-BN) is harder than a diamond for its indentation strength.
  • We don’t have a third con. Don’t lose your keys or Magnetic Key Cutting Card!

Pick up this incredibly secure padlock here.

2. Abloy Protec2 PL 362

Finnish company Abloy is known worldwide for outstanding high-security locks. No list of the best would be complete without at least one of their amazing padlocks included. Plenty of experts will attest to the incredible benefits of these robust padlocks.

One of the best features of these locks is the ability to create master keying or key alike systems. For those who need to secure more than one container or area, these are exceptional locks for that purpose.

“High shoulders” guard against shackle cutting. A free spinning, hardened protective plate gives this lock maximum protection against drilling. The disk blocking rotation inside makes picking the Protec2 PL 362 functionally impossible. 

Protec 2 Keys

The original Protec system is stellar. It is more than sufficient for most high-security needs. Even so, when you need the best of the best, the upgraded Protec 2 has a couple of upgraded features that are nice to have. After all, even a locksmith can be a lousy spouse, and sometimes you need better protection.

The front of the lock on this generation got an upgrade. The result is better drill resistance. Keys themselves are now anti-wear. If you plan to unlock (and subsequently re-lock) your Protec 2 often, you’ll find these keys don’t wear out as easily as previous generations. Keep in mind, ‘often’ refers to tens of thousands of uses causing wear at the tip of keys.

Really Tough Keys

Furthermore, the keys are extremely secure against copying. Protec 2 keys have a free-moving ball bearing. The added element means that duplication isn’t something that a random home improvement store can do.

You have to order new keys from Abloy itself. Hence you should keep your receipts somewhere secure. For digital transactions, you may want to store the file in an off-site password locked file.

Although most people feel safe enough stashing info on their home or work computers, you only have to read this site to learn how easy it is for your crummy spouse to illegally videotape or keystroke log your actions.


  • Abloy employs its own ‘pick proof’ rotating disc cylinder system inside each lock. Doing this allows for a wide range of master keying options. As a result, its incredibly unlikely that another Abloy lock key would even fit in your lock, let alone open it.
  • You can get SCEC endorsed secure area applications. However, to do this, you will need to get a padlock fitted with an ABLOY PROTEC or a Disklock Pro cylinder.
  • A Grade 6 rating is the highest *CEN a company can get. This lock is approved for industrial and even military use.


  • Great locks are not inexpensive. Nevertheless, if you want the top of the line security, you need to order it. You can never be too safe when the stakes are high.
  • If a locksmith could open this padlock, and they can’t, it would cost a small fortune. Over two billion possible key configurations mean that you will not be able to get into this lock if you misplace your key. I’m aware that I’ve said this before, but the biggest downside to an exceptional lock is that you can lock yourself out of it.
  • You may never respect an ordinary padlock again. Try not to be angry that you paid for cheap locks. Instead, chalk it up to learning experience.

Check out Abloy right here.

* Central European Norm or CEN is one of several standards used to grade locks. CEN goes from 1-6, with six being the best there is. A CEN 1 is approved for general use to secure, say a gate. Insurance companies approve these locks for basic safety. Meanwhile, five or six is for high-security installations.

3. Sargent & Greenleaf 951C

For an elite lock beyond any normal need, the Sargent & Greenleaf 951C. If your stalker or crazy ex is ex-special forces or worked for Blackwater, then this is probably what you need to keep them out. The original 951 lock is government only, but the 951C is the next best thing. 

The 951C comes with a high-security Medeco biaxial key cylinder. Possibly even more importantly, the body and shackle use exotic barrier materials. This inclusion helps resist drilling, cutting, and sawing for maximum security.

Government Work

S&G has been in business for over 160 years, and they bring all their experience to the table for this lock. They make locks that meet mil-spec MIL-DTL-43607J. In layman’s terms, they’re up to snuff for US defense purposes per the DoJ.

This lock is the civilian version. Happily, the significant difference is your unrestricted keyway. A restricted keyway only gets service from a single locksmith. Most importantly, while it’s only slightly less secure than the government issue, it’s also probably easier to get a duplicate key.

Life may be uncertain, but you can have security beyond a reasonable doubt. Plus the company provides instructions on use and servicing this lock online. You don’t need to worry about losing a physical booklet and having to wait for a shipping carrier to bring you a new one.


  • Efficiency at it’s finest, in case you need to rekey your lock at any point in the future. You can disassemble this lock easily if you have the right control key.
  • The 10 3/4″ steel chain and fastening plate are included and already attached to the lock. This allows for easy installation with little or no need to buy additional items for immediate use.
  • This lock is key retaining. Luckily this means you cannot walk away with your key until you lock up. No one wants to admit it, but we all have our off days, and accidents can happen. A key retaining lock helps avoid one of the biggest mistakes you can make with any lock, which is not using it.


  • A 1-Year Manufacturer Warranty begins on the date they ship out the lock to your retailer. Make sure you know the shipment date to avoid any hassles in the future.
  • You cannot get the restricted keyway commercially at any price. Sadly, this means getting duplicate keys is slightly easier than with a lock that has this feature.
  • The incredible level of forced entry resistance on this lock means you may not be able to break into your own container, yard, or other lockable items and areas in an emergency. Use with caution.

Get your maximum S&G security padlock here.

4. ABUS Granit ConHasp with Rekeyable Padlock

If you want to secure something a little larger, like a storage unit or gate, this combination lock and cover are ideal. The company cares enough to remind it’s clients that you need a hasp as capable as your lock or you’ll be wasting your money.  You have to respect a company that cares and also makes a superior product.

In addition to the lock and cover, all mounting hardware comes standard. You’ll have everything you need to secure the container of your choice with this excessively beefy lock setup.

Fifteen Pound Lock

This weighty dynamo should keep anyone out. It’s maximally resistant to all forms of attack from saws to hammers and everything in between. Besides all the remarkable engineering that goes into this lock set, the ABU company also uses a special welding technique that increases the lock durability.


  • This lock withstands a pulling force of over six tons. Leverage attacks are utterly useless against this industrial bad boy.
  • Every part of the ABUS 215/100 Granit ConHasp with 37RK/70HB100 High-Security Rekeyable Padlock is corrosion resistant. Since they’re made to go on trucks and cargo containers, the Granit ConHasps need to be able to resist salt water if they’re shipped overseas.
  • You can use the outer lock protector with a different padlock. Likewise, you can use the padlock by itself. Together they are a near-unbreakable combo.


  • Granit makes several 37RK locks with slightly different features. The model included with this offer isn’t specified.
  • If your hasp isn’t up to the job, this padlock and cover won’t save you. Though they are leverage resistant, a bad hasp will pull out long before the lock on it breaks.
  • Repair or replacement is at the manufacturer’s discretion if the product fails or happens to be faulty.

Upgrade to this heavy duty package here.

5. FJM Security SPSA60-KD

The final spot on this list goes to a small but powerful padlock. There are so many unique features to the FJM SPSA60-KD, but most instantly noticeable is the shape. The “D” shaped design has nothing in common with the everyday padlocks we see everywhere.

With its guarded access and European keyway, the SPSA60-KD is not what most thieves will expect to see. They may not know what to make of this bizarre but secure lock. You’ll receive four keys to assure you always have access to your property.

No Weakness

The heel to toe locking gives you greater security without the weak points of lesser locks. All the components are all internal brass and stainless steel. Any thief dumb enough to take on this lock will surely lose. Every set is keyed differently to add a layer of security. Additionally, the lock retains your key until fully locked.


  • A freely rotating shackle makes cutting exceedingly tricky. Most saws need a stable surface to get purchase.
  • No internal springs mean you never need to concern yourself with worn out spring action stopping your lock from closing or opening correctly.
  • Triple chrome plated.


  • Double the size (or more) of a run-of-the-mill padlock, the shackle diameter is also larger. You’ll need to know the diameter of the space it needs to pass through before purchasing.
  • Your unstable spouse will come totally unhinged trying to open this lock. Okay, perhaps that’s an exaggeration. Still, anyone is likely to get frustrated if they need to get past one of these lovely locks.

Find more information on FJM locks here.

*Bonus- Low Budget High-Security

Master Lock Pro Series 6271NKA-1

Master lock, while known for its ubiquitous silver locks, makes more complex options as well. The standard fare is fine for locking up your gym shorts. Unsurprisingly, they’ve branched out over the last 98 years. You can find smaller locks and plenty of advanced models as well.

If you’re seeking a low-cost, higher security option for your valuables the Master Lock Pro Series Hidden Shackle 6271NKA-1 Disc Padlock is a good budget-friendly choice. 

Safety Features

All the 6271NKA-1 models come with BumpStop Advanced Cylinder Technology and a six pin, removable cylinder. Rekeying is easy, but busting this lock is hard. The fully enclosed (from the front) boron alloy shackle is incredibly difficult to reach and even more problematic to cut. 

Pry-resistant features combine with a thick-bodied brawny disc shape that is far tougher than a standard lock. The die-cast zinc alloy offers high strength (to 60,000 psi) to ward off attackers and prevent breakage. You won’t have to worry with this lock on your side.

Master the possibilities here.

Final Thoughts

No one intends to ignore security. We all need to feel safe and protected. Yet we ‘forget’ to take serious steps toward theft prevention. Surely we don’t have to worry about something like that, do we? The truth is, you’ll never know until it’s too late.

The safest bet is always to protect yourself preemptively. If you don’t need this level of security, it will never hurt to have it. When you do, it’s often too late to start looking. Don’t get caught with your (proverbial or literal) pants down. No one else is going to cover your… bases. Get a lock that won’t let you down even if your partner does.

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