Locksmith Services

A lock is a mechanical or electronic fastening device that is released by a physical object (such as a key, keycard, fingerprint, RFID card, security token or coin), by supplying secret information (such as a number or letter permutation or password), by a combination thereof, or it may only be able to be opened from one side, such as a door chain.

A key is a device that is used to operate a lock (to lock or unlock it). A typical key is a small piece of metal consisting of two parts: the bit or blade, which slides into the keyway of the lock and distinguishes between different keys, and the bow, which is left protruding so that torque can be applied by the user. In its simplest implementation, a key operates one lock or set of locks that are keyed alike, a lock/key system where each similarly keyed lock requires the same, unique key.

The key serves as a security token for access to the locked area; locks are meant to only allow persons having the correct key to open it and gain access. In more complex mechanical lock/key systems, two different keys, one of which is known as the master key, serve to open the lock. Common metals include brass, plated brass, nickel silver, and steel. The act of opening a lock without a key is called lock picking.

Locks have been in use for over 6000 years, with one early example discovered in the ruins of Nineveh, the capital of ancient Assyria.^[1] Locks such as this were developed into the Egyptian wooden pin lock, which consisted of a bolt, door fixture or attachment, and key. When the key was inserted, pins within the fixture were lifted out of drilled holes within the bolt, allowing it to move. When the key was removed, the pins fell part-way into the bolt, preventing movement.^[2]

The warded lock was also present from antiquity and remains the most recognizable lock and key design in the Western world. The first all-metal locks appeared between the years 870 and 900, and are attributed to English craftsmen.^[3] It is also said that the key was invented by Theodorus of Samos in the 6th century BC.^[1]

The Romans invented metal locks and keys and the system of security provided by wards.^[4]

Affluent Romans often kept their valuables in secure locked boxes within their households, and wore the keys as rings on their fingers. The practice had two benefits: It kept the key handy at all times, while signaling that the wearer was wealthy and important enough to have money and jewellery worth securing.^[5]

A special type of lock, dating back to the 17th–18th century, although potentially older as similar locks date back to the 14th century, can be found in the Beguinage of the Belgian city Lier.^[6][7] These locks are most likely Gothic locks, that were decorated with foliage, often in a V-shape surrounding the keyhole.^[8] They are often called drunk man's lock, as these locks were, according to certain sources, designed in such a way a person can still find the keyhole in the dark, although this might not be the case as the ornaments might have been purely aesthetic.^[6][7] In more recent times similar locks have been designed.^[9][10]

With the onset of the Industrial Revolution in the late 18th century and the concomitant development of precision engineering and component standardization, locks and keys were manufactured with increasing complexity and sophistication.^[11]

The lever tumbler lock, which uses a set of levers to prevent the bolt from moving in the lock, was invented by Robert Barron in 1778.^[12] His double acting lever lock required the lever to be lifted to a certain height by having a slot cut in the lever, so lifting the lever too far was as bad as not lifting the lever far enough. This type of lock is still used today.^[13]

The lever tumbler lock was greatly improved by Jeremiah Chubb in 1818.^[12] A burglary in Portsmouth Dockyard prompted the British Government to announce a competition to produce a lock that could be opened only with its own key.^[5] Chubb developed the Chubb detector lock, which incorporated an integral security feature that could frustrate unauthorized access attempts and would indicate to the lock's owner if it had been interfered with. Chubb was awarded £100 after a trained lock-picker failed to break the lock after 3 months.^[14]

In 1820, Jeremiah joined his brother Charles in starting their own lock company, Chubb. Chubb made various improvements to his lock: his 1824 improved design did not require a special regulator key to reset the lock; by 1847 his keys used six levers rather than four; and he later introduced a disc that allowed the key to pass but narrowed the field of view, hiding the levers from anybody attempting to pick the lock.^[15] The Chubb brothers also received a patent for the first burglar-resisting safe and began production in 1835.

The designs of Barron and Chubb were based on the use of movable levers, but Joseph Bramah, a prolific inventor, developed an alternative method in 1784. His lock used a cylindrical key with precise notches along the surface; these moved the metal slides that impeded the turning of the bolt into an exact alignment, allowing the lock to open. The lock was at the limits of the precision manufacturing capabilities of the time and was said by its inventor to be unpickable. In the same year Bramah started the Bramah Locks company at 124 Piccadilly, and displayed the "Challenge Lock" in the window of his shop from 1790, challenging "...the artist who can make an instrument that will pick or open this lock" for the reward of £200. The challenge stood for over 67 years until, at the Great Exhibition of 1851, the American locksmith Alfred Charles Hobbs was able to open the lock and, following some argument about the circumstances under which he had opened it, was awarded the prize. Hobbs' attempt required some 51 hours, spread over 16 days.

The earliest patent for a double-acting pin tumbler lock was granted to American physician Abraham O. Stansbury in England in 1805,^[16] but the modern version, still in use today, was invented by American Linus Yale Sr. in 1848.^[17] This lock design used pins of varying lengths to prevent the lock from opening without the correct key. In 1861, Linus Yale Jr. was inspired by the original 1840s pin-tumbler lock designed by his father, thus inventing and patenting a smaller flat key with serrated edges as well as pins of varying lengths within the lock itself, the same design of the pin-tumbler lock which still remains in use today.^[18] The modern Yale lock is essentially a more developed version of the Egyptian lock.

Despite some improvement in key design since, the majority of locks today are still variants of the designs invented by Bramah, Chubb and Yale.

• 
  Pin tumbler lock: without a key in the lock, the driver pins (blue) are pushed downwards, preventing the plug (yellow) from rotating.
• 
  Wafer tumbler lock: without a key in the lock, the wafers (red) are pushed down by springs. The wafers nestle into a groove in the lower part of the outer cylinder (green) preventing the plug (yellow) from rotating.
• 
  Tubular lock: the key pins (red) and driver pins (blue) are pushed towards the front of the lock, preventing the plug (yellow) from rotating. The tubular key has several half-cylinder indentations which align with the pins.

A warded lock uses a set of obstructions, or wards, to prevent the lock from opening unless the correct key is inserted. The key has notches or slots that correspond to the obstructions in the lock, allowing it to rotate freely inside the lock. Warded locks are typically reserved for low-security applications as a well-designed skeleton key can successfully open a wide variety of warded locks.

The pin tumbler lock uses a set of pins to prevent the lock from opening unless the correct key is inserted. The key has a series of grooves on either side of the key's blade that limit the type of lock the key can slide into. As the key slides into the lock, the horizontal grooves on the blade align with the wards in the keyway allowing or denying entry to the cylinder. A series of pointed teeth and notches on the blade, called bittings, then allow pins to move up and down until they are in line with the shear line of the inner and outer cylinder, allowing the cylinder or cam to rotate freely and the lock to open. An additional pin called the master pin is present between the key and driver pins in locks that accept master keys, to allow the plug to rotate at multiple pin elevations.

A wafer tumbler lock is similar to the pin tumbler lock and works on a similar principle. However, unlike the pin lock (where each pin consists of two or more pieces) each wafer is a single piece. The wafer tumbler lock is often incorrectly referred to as a disc tumbler lock, which uses an entirely different mechanism. The wafer lock is relatively inexpensive to produce and is often used in automobiles and cabinetry.

The disc tumbler lock or Abloy lock is composed of slotted rotating detainer discs.

The lever tumbler lock uses a set of levers to prevent the bolt from moving in the lock. In its simplest form, lifting the tumbler above a certain height will allow the bolt to slide past. Lever locks are commonly recessed inside wooden doors or on some older forms of padlocks, including fire brigade padlocks.

A magnetic keyed lock is a locking mechanism whereby the key utilizes magnets as part of the locking and unlocking mechanism. A magnetic key would use from one to many small magnets oriented so that the North and South poles would equate to a combination to push or pull the lock's internal tumblers thus releasing the lock.

An electronic lock works by means of an electric current and is usually connected to an access control system. In addition to the pin and tumbler used in standard locks, electronic locks connect the bolt or cylinder to a motor within the door using a part called an actuator. Types of electronic locks include the following:

A keycard lock operates with a flat card of similar dimensions as a credit card. In order to open the door, one needs to successfully match the signature within the keycard.

The lock in a typical remote keyless system operates with a smart key radio transmitter. The lock typically accepts a particular valid code only once, and the smart key transmits a different rolling code every time the button is pressed. Generally the car door can be opened with either a valid code by radio transmission, or with a (non-electronic) pin tumbler key. The ignition switch may require a transponder car key to both open a pin tumbler lock and also transmit a valid code by radio transmission.

A smart lock is an electromechanics lock that gets instructions to lock and unlock the door from an authorized device using a cryptographic key and wireless protocol. Smart locks have begun to be used more commonly in residential areas, often controlled with smartphones.^[19][20] Smart locks are used in coworking spaces and offices to enable keyless office entry.^[21] In addition, electronic locks cannot be picked with conventional tools.

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Locksmithing is a traditional trade, and in most countries requires completion of an apprenticeship. The level of formal education required varies from country to country, from no qualifications required at all in the UK,^[22] to a simple training certificate awarded by an employer, to a full diploma from an engineering college. Locksmiths may be commercial (working out of a storefront), mobile (working out of a vehicle), institutional, or investigational (forensic locksmiths). They may specialize in one aspect of the skill, such as an automotive lock specialist, a master key system specialist or a safe technician. Many also act as security consultants, but not all security consultants have the skills and knowledge of a locksmith.^{[citation needed]}

Historically, locksmiths constructed or repaired an entire lock, including its constituent parts. The rise of cheap mass production has made this less common; the vast majority of locks are repaired through like-for-like replacements, high-security safes and strongboxes being the most common exception. Many locksmiths also work on any existing door hardware, including door closers, hinges, electric strikes, and frame repairs, or service electronic locks by making keys for transponder-equipped vehicles and implementing access control systems.

Although the fitting and replacement of keys remains an important part of locksmithing, modern locksmiths are primarily involved in the installation of high quality lock-sets and the design, implementation, and management of keying and key control systems. Locksmiths are frequently required to determine the level of risk to an individual or institution and then recommend and implement appropriate combinations of equipment and policies to create a "security layer" that exceeds the reasonable gain of an intruder.^{[citation needed]}

A smart key is a vehicular passive entry system developed by Siemens in 1995 and introduced by Mercedes-Benz under the name "Keyless-Go" in 1998 on the W220 S-Class,^[1] after the design patent was filed by Daimler-Benz on May 17, 1997.^[2]

Numerous manufacturers subsequently developed similar passive systems that unlock a vehicle on approach — while the key remains pocketed by the user.

The smart key allows the driver to keep the key fob pocketed when unlocking, locking and starting the vehicle. The key is identified via one of several antennas in the car's bodywork and an ISM band radio pulse generator in the key housing. Depending on the system, the vehicle is automatically unlocked when a button or sensor on the door handle or trunk release is pressed. Vehicles with a smart-key system have a mechanical backup, usually in the form of a spare key blade supplied with the vehicle. Some manufacturers hide the backup lock behind a cover for styling.

Vehicles with a smart-key system can disengage the immobilizer and activate the ignition without inserting a key in the ignition, provided the driver has the key inside the car. On most vehicles, this is done by pressing a starter button or twisting an ignition switch.

When leaving a vehicle that is equipped with a smart-key system, the vehicle is locked by either pressing a button on a door handle, touching a capacitive area on a door handle, or simply walking away from the vehicle. The method of locking varies across models.

Some vehicles automatically adjust settings based on the smart key used to unlock the car. User preferences such as seat positions, steering wheel position, exterior mirror settings, climate control (e.g. temperature) settings, and stereo presets are popular adjustments. Some models, such as the Ford Escape, even have settings to prevent the vehicle from exceeding a maximum speed if it has been started with a certain key.

In 2005, the UK motor insurance research expert Thatcham introduced a standard for keyless entry, requiring the device to be inoperable at a distance of more than 10 cm from the vehicle.^{[citation needed]} In an independent test, the Nissan Micra's system was found to be the most secure, while certain BMW and Mercedes keys failed, being theoretically capable of allowing cars to be driven away while their owners were refueling.^[3] Despite these security vulnerabilities, auto theft rates have decreased 7 percent between 2009 and 2010, and the National Insurance Crime Bureau credits smart keys for this decrease.^[4][5]

SmartKeys were developed by Siemens in the mid-1990s and introduced by Mercedes-Benz in 1997 to replace the infrared security system introduced in 1989. Daimler-Benz filed the first patents for SmartKey on February 28, 1997, in German patent offices, with multifunction switchblade key variants following on May 17, 1997.^[6][7][8][9] The device entailed a plastic key to be used in place of the traditional metal key. Electronics that control locking systems and the ignitions made it possible to replace the traditional key with a sophisticated computerized "Key". It is considered a step up from remote keyless entry. The SmartKey adopts the remote control buttons from keyless entry, and incorporates them into the SmartKey fob.

Once inside a Mercedes-Benz vehicle, the SmartKey fob, unlike keyless entry fobs, is placed in the ignition slot where a starter computer verifies the rolling code. Verified in milliseconds, it can then be turned as a traditional key to start the engine. The device was designed with the cooperation of Siemens Automotive and Huf exclusively for Mercedes-Benz, but many luxury manufacturers have implemented similar technology based on the same idea.^{[citation needed]} In addition to the SmartKey, Mercedes-Benz now integrates as an option Keyless Go; this feature allows the driver to keep the SmartKey in their pocket, yet giving them the ability to open the doors, trunk as well as starting the car without ever removing it from their pocket.

The SmartKey's electronics are embedded in a hollow, triangular piece of plastic, wide at the top, narrow at the bottom, squared-off at the tip with a half-inch-long insert piece. The side of the SmartKey also hides a traditional Mercedes-Benz key that can be pulled out from a release at the top. The metal key is used for valet purposes such as locking the glove compartment and/or trunk before the SmartKey is turned over to a parking attendant. Once locked manually, the trunk cannot be opened with the SmartKey or interior buttons. The key fob utilizes a radio-frequency transponder to communicate with the door locks, but it uses infrared to communicate with the engine immobilizer system. The original SmartKeys had a limited frequency and could have only been used in line-of-sight for safety purposes. The driver can also point the smart key at the front driver side door while pushing and holding the unlock button on the SmartKey and the windows and the sunroof will open in order to ventilate the cabin. Similarly, if the same procedure is completed while holding the lock button, the windows and sunroof will close. In cars equipped with the Active Ventilated Seats, the summer opening feature will activate seat ventilation in addition to opening the windows and sunroof.^{[citation needed]}

Display Key is a type of smart key developed by BMW that includes a small LCD color touchscreen on it. It performs the standard functions that a key fob would normally do such as locking, unlocking & keyless start, but because of the screen the user can also perform a number of the features from BMW's app. One of which includes commanding the car to self park from the key if your car has self parking capability. The key is currently available for the 3 Series, 4 Series, 5 Series, 6 Series, 7 Series, 8 Series, X3, X4, X5, X6, and X7. The key is rechargeable and will last about 3 weeks. It can be charged via a micro USB port on the side or wirelessly on the center console.

Keyless Go (also: Keyless Entry / Go; Passive Entry / Go) is Mercedes' term for an automotive technology which allows a driver to lock and unlock a vehicle without using the corresponding SmartKey buttons.^[10] Once a driver enters a vehicle with an equipped Keyless Go SmartKey or Keyless Go wallet-size card, they have the ability to start and stop the engine, without inserting the SmartKey. A transponder built within the SmartKey allows the vehicle to identify a driver. An additional safety feature is integrated into the vehicle, making it impossible to lock a SmartKey with Keyless Go inside a vehicle.

The system works by having a series of LF (low frequency 125 kHz) transmitting antennas both inside and outside the vehicle. The external antennas are located in the door handles. When the vehicle is triggered, either by pulling the handle or touching the handle, an LF signal is transmitted from the antennas to the key. The key becomes activated if it is sufficiently close and it transmits its ID back to the vehicle via RF (Radio frequency >300 MHz) to a receiver located in the vehicle. If the key has the correct ID, the PASE module unlocks the vehicle.

The hardware blocks of a Keyless Entry / Go Electronic control unit ECU are based on its functionality:

• transmitting low-frequency LF signals via the 125 kHz power amplifier block
• receiving radio frequency RF signals (> 300 MHz) from the built-in ISM receiver block
• encrypting and decrypting all relevant data signals (security)
• communicating relevant interface signals with other electronic control units
• microcontroller

The smart key determines if it is inside or outside the vehicle by measuring the strength of the LF fields. In order to start the vehicle, the smart key must be inside the vehicle.

It is important that the vehicle can't be started when the user and therefore the smart key is outside the vehicle. This is especially important at fueling stations where the user is very close to the vehicle. The internal LF field is allowed to overshoot by a maximum of 10 cm to help minimise this risk. Maximum overshoot is usually found on the side windows where there is very little attenuation of the signal.

A second scenario exists under the name "relay station attack" (RSA). The RSA is based on the idea of reducing the long physical distance between the car and the regular car owner's SmartKey. Two relay stations will be needed for this: The first relay station is located nearby the car and the second is close to the SmartKey. So on first view, the Keyless Entry / Go ECU and the SmartKey could communicate together. A third person at the car could pull the door handle and the door would open. However, in every Keyless Entry / Go system provisions exist to avoid a successful two-way communication via RSA. Some of the most known are:

• measuring group delay time to detect illegal high values
• measuring third-order intercept point to detect illegal intermodulation products
• measuring field strength of the electric field
• measuring the response time of 125 kHz LC circuit
• using a more complex modulation (i.e. quadrature amplitude modulation) which can't be demodulated and modulated by a simple relay station

Furthermore, Keyless Entry / Go communicates with other Control Units within the same vehicle. Depending on the electric car architecture, the following are some Control Systems that can be enabled or disabled:

• ESCL Electric Steering Column Lock
• EIS Electronic Ignition Switch
• Central door locking system
• Immobiliser
• Engine Control Unit (Motor management system)
• BCU Body control unit

Another possibility is using a motion sensor within the key fob.^[11][12]

Dead spots are a result of the maximum overshoot requirement from above. The power delivered to the internal LF antennas has to be tuned to provide the best performance i.e. minimum dead spots and maximum average overshoot. Dead spots are usually near the extremities of the vehicle e.g. the rear parcel shelf.

If the battery in the smart key becomes depleted, it is necessary for there to be a backup method of opening and starting the vehicle. Opening is achieved by an emergency (fully mechanical) key blade usually hidden in the smart key. On many cars emergency starting is achieved by use of an inductive coupling. The user either has to put the key in a slot or hold it near a special area on the cockpit, where there is an inductive coil hidden behind which transfers energy to a matching coil in the dead key fob using inductive charging.

Slots have proven to be problematic, as they can go wrong and the key becomes locked in and cannot be removed. Another problem with the slot is it can't compensate for a fob battery below certain operating threshold. Most smart key batteries are temperature sensitive causing the fob to become intermittent, fully functional, or inoperative all in the same day.

A Keyless Entry / Go system should be able to detect and handle most of the following cases:

• SmartKey Transponder was forgotten in the rear trunk
• More than one SmartKey is present inside the car
• SmartKey getting lost during the drive
• Smartkey battery low (Limp-Home)

A test by ADAC revealed that 20 car models with Keyless Go could be entered and driven away without the key.^{[13][14][15][16]} In 2014, 6,000 cars (about 17 per day) were stolen using keyless entry in London.^[17]

• Remote keyless system
• Transponder car key

• Relay Attacks on Passive Keyless Entry and Start Systems in Modern Cars
• Security Flaws of Remote

Locksmithing is the work of creating and bypassing locks. Locksmithing is a traditional trade and in many countries requires completion of an apprenticeship. The level of formal education legally required varies by country, ranging from no formal education to a training certificate awarded by an employer, or a full diploma from an engineering college, along with time spent as an apprentice.

A lock is a mechanism that secures buildings, rooms, cabinets, objects, or other storage facilities. A "smith" is a metalworker who shapes metal pieces, often using a forge or mould, into useful objects or to be part of a more complex structure. Thus locksmithing, as its name implies, is the assembly and designing of locks and their respective keys by hand. Most locksmiths use both automatic and manual cutting tools to mold keys, with many of these tools being powered by batteries or mains electricity.

Locks have been constructed for over 2500 years, initially out of wood and later out of metal.^[1] Historically, locksmiths would make the entire lock, working for hours hand cutting screws and doing much file-work. Lock designs became significantly more complicated in the 18th century, and locksmiths often specialized in repairing or designing locks.

Although replacing lost keys for automobiles and homes, as well as rekeying locks for security purposes, remains an important part of locksmithing, a 1976 US Government publication noted that modern locksmiths are primarily involved in installing high-quality lock-sets and managing keying and key control systems.

Most locksmiths also provide electronic lock services, such as programming smart keys for transponder-equipped vehicles and implementing access control systems to protect individuals and assets for large institutions.^[2] Many also specialise in other areas such as:

• Auto Locksmithing
• Safes

In Australia, prospective locksmiths are required to take a Technical and Further Education (TAFE) course in locksmithing, completion of which leads to issuance of a Level 3 Australian Qualifications Framework certificate, and complete an apprenticeship. They must also pass a criminal records check certifying that they are not currently wanted by the police. Apprenticeships can last one to four years. Course requirements are variable: there is a minimal requirements version that requires fewer total training units, and a fuller version that teaches more advanced skills, but takes more time to complete. Apprenticeship and course availability vary by state or territory.^[3]

In Ireland, licensing for locksmiths was introduced in 2016,^[4] with locksmiths having to obtain a Private Security Authority license. The Irish Locksmith Organisation has 50 members with ongoing training to ensure all members are up-to-date with knowledge and skills.

In the UK, there is no current government regulation for locksmithing, so effectively anyone can trade and operate as a locksmith with no skill or knowledge of the industry.^[5]

Fifteen states in the United States require licensure for locksmiths. Nassau County and New York City in New York State, and Hillsborough County and Miami-Dade County in Florida have their own licensing laws.^[6] State and local laws are described in the table below. 15 states require locksmith licensing: Alabama, California, Connecticut, Illinois, Louisiana, Maryland, Nebraska, New Jersey, Nevada, North Carolina, Oklahoma, Oregon, Tennessee, Texas and Virginia

Locksmiths may be commercial (working out of a storefront), mobile (working out of a vehicle), institutional (employed by an institution) or investigatory (forensic locksmiths) or may specialize in one aspect of the skill, such as an automotive lock specialist, a master key system specialist or a safe technician.^[2] Many locksmiths also work as security consultants, but not all security consultants possess locksmithing skills. Locksmiths are frequently certified in specific skill areas or to a level of skill within the trade. This is separate from certificates of completion of training courses. In determining skill levels, certifications from manufacturers or locksmith associations are usually more valid criteria than certificates of completion. Some locksmiths decide to call themselves "Master Locksmiths" whether they are fully trained or not, and some training certificates appear quite authoritative.

The majority of locksmiths also work on any existing door hardware, not just locking mechanisms. This includes door closers, door hinges, electric strikes, frame repairs and other door hardware.

The issue of full disclosure was first raised in the context of locksmithing, in a 19th-century controversy regarding whether weaknesses in lock systems should be kept secret in the locksmithing community, or revealed to the public.

According to A. C. Hobbs:

A commercial, and in some respects a social doubt has been started within the last year or two, whether or not it is right to discuss so openly the security or insecurity of locks. Many well-meaning persons suppose that the discussion respecting the means for baffling the supposed safety of locks offers a premium for dishonesty, by showing others how to be dishonest. This is a fallacy. Rogues are very keen in their profession, and know already much more than we can teach them respecting their several kinds of roguery.

Rogues knew a good deal about lock-picking long before locksmiths discussed it among themselves, as they have lately done. If a lock, let it have been made in whatever country, or by whatever maker, is not so inviolable as it has hitherto been deemed to be, surely it is to the interest of honest persons to know this fact, because the dishonest are tolerably certain to apply the knowledge practically; and the spread of the knowledge is necessary to give fair play to those who might suffer by ignorance.

It cannot be too earnestly urged that an acquaintance with real facts will, in the end, be better for all parties. Some time ago, when the reading public was alarmed at being told how London milk is adulterated, timid persons deprecated the exposure, on the plea that it would give instructions in the art of adulterating milk; a vain fear, milkmen knew all about it before, whether they practised it or not; and the exposure only taught purchasers the necessity of a little scrutiny and caution, leaving them to obey this necessity or not, as they pleased.

-- From A. C. Hobbs (Charles Tomlinson, ed.), Locks and Safes: The Construction of Locks. Published by Virtue & Co., London, 1853 (revised 1868).

• William F. Banham, founder of Banham Security, invented the first automatic latch bolt lock in 1926 after a series of burglaries on his wife's dress shop. He opened up his own locksmith shop on Oxford Street, London, and offered £25 to anyone who could pick or break one of his patented locks^[25][26] Banham Group still offer the patented locks.^[27][28][29]
• Robert Barron patented a double-acting tumbler lock in 1778, the first reasonable improvement in lock security.
• Joseph Bramah patented the Bramah lock in 1784.^[30] It was considered unpickable for 67 years until A.C. Hobbs picked it, taking over 50 hours.^[31]
• Jeremiah Chubb patented his detector lock in 1818. It won him the reward offered by the Government for a lock that could not be opened by any but its own key.
• James Sargent described the first successful key-changeable combination lock in 1857. His lock became popular with safe manufacturers and the United States Treasury Department. In 1873, he patented a time lock mechanism, the prototype for those used in contemporary bank vaults.
• Samuel Segal of the Segal Lock and Hardware Company invented the first jimmy-proof locks in 1916.
• Harry Soref founded the Master Lock Company in 1921 and patented an improved padlock in 1924 with a patent lock casing constructed out of laminated steel.
• Linus Yale Sr. invented a pin tumbler lock in 1848.
• Linus Yale Jr. improved upon his father's lock in 1861, using a smaller, flat key with serrated edges that is the basis of modern pin-tumbler locks. Yale Jr. developed the modern combination lock in 1862.
• Alfred Charles Hobbs demonstrated the inadequacy of several respected locks of the time in 1851 at The Great Exhibition, and popularized the practice of full disclosure.

• Associated Locksmiths of America
• Door security
• Glossary of locksmithing terms
• Immobiliser
• Locksport
• Master Locksmiths Association
• The National Locksmith

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