High-security locks are cylinders and lock bodies that exceed ANSI/BHMA Grade 1 specifications in pick resistance, drill resistance, and key control. The three most specified high-security brands in North America are Medeco, Mul-T-Lock, and Abloy — each using a different mechanical principle to achieve a level of protection that standard pin tumbler cylinders cannot match. For locksmiths, high-security installations represent higher margin jobs, restricted key supply relationships, and the kind of commercial account that generates recurring service revenue.
Understanding what actually differentiates high-security locks — not just the marketing, but the mechanical principles — lets you have an informed conversation with clients about whether a high-security upgrade is warranted and which brand is appropriate for their threat model.
What Makes a Lock "High-Security"
The term high-security is used loosely, but in professional practice it refers to cylinders that meet or exceed ANSI/BHMA 156.30 (High Security Cylinders) and UL 437 certification requirements. These standards test for resistance to specific attack methods:
- Picking — The cylinder must withstand pick manipulation for a defined time period
- Drilling — Hardened steel components must resist drill bits long enough to deter opportunistic attack
- Key duplication — The blank must be restricted or patented to prevent unauthorized copying
- Key control — The manufacturer must maintain records of key sales and provide documentation
Standard residential cylinders (Schlage B-series, Kwikset) are designed to be affordable and convenient, not to resist skilled attack. A competent locksmith can pick most standard cylinders in under a minute. High-security cylinders change the economics of attack significantly.
Medeco
Medeco cylinders use two distinct security mechanisms working together: angled cuts and rotating pins.
Standard pin tumbler cylinders use vertical cuts on the key blade. Medeco keys use cuts at three angles — left, right, and center — each corresponding to a different pin rotation position. To lift a pin to the shear line, both the height (standard) and the rotation (Medeco-specific) must be correct simultaneously.
This dual-axis requirement makes picking substantially harder. Standard picking techniques that manipulate pin height alone do not work — you must also rotate each pin to its correct position, which requires a different tool and technique simultaneously.
Medeco cylinders also use a sidebar — an additional locking bar that must be properly aligned (requiring correct key cuts and pin rotations) before the plug can rotate. The sidebar adds a third element of security beyond the standard shear line.
Key control: Medeco blanks are patented and restricted. Keys can only be duplicated by authorized Medeco dealers, and each duplication is logged. This is genuine key control — not a "do not duplicate" stamp.
Mul-T-Lock
Mul-T-Lock uses a pin-within-a-pin design. Each pin column contains two pin elements: an outer pin with a hole in it, and an inner "telescoping" pin that sits inside the outer pin. Both elements must align simultaneously at the shear line for the lock to open.
This design dramatically increases the number of possible combinations and makes standard picking attacks ineffective. Picking a standard cylinder requires lifting N pins to the shear line. Picking a Mul-T-Lock requires lifting N outer pins while simultaneously positioning N inner pins — a near-impossible task with standard picking tools.
Mul-T-Lock cylinders also incorporate hardened steel anti-drill inserts protecting the pins and shear line. The physical resistance to drill attack is among the highest of any commercially available cylinder.
Key control: Mul-T-Lock uses a patented "Interactive" key system in their higher-security lines, with keys that require a floating element to move correctly during insertion. Blanks are restricted and available only through authorized distributors.
Abloy
Abloy uses a completely different mechanism: rotating discs instead of pins. There are no springs, no pins, and no driver pins in an Abloy cylinder. Instead, the cylinder contains a series of hardened steel discs with cut-outs at different positions. The key rotates each disc to a specific angle, and only when all discs are correctly positioned does the locking bar disengage.
Because there are no springs and no pins, picking in the traditional sense is impossible. The attack methods that work against pin tumbler cylinders — single pin picking, raking, bumping — have no effect on a disc-detainer design.
Abloy's PROTEC2 line is widely regarded as the most physically secure cylinder available in the commercial market. It carries extremely high ratings against picking, drilling, and environmental attack.
Key control: Abloy uses patented key profiles and maintains strict control over blank distribution. The PROTEC2 system uses laser-cut keys that are extremely difficult to duplicate without factory tooling.
Choosing the Right High-Security Brand
The right choice depends on the client's threat model and budget:
- Medeco — Best for clients who need documented key control combined with strong pick and drill resistance. Common in law firms, medical offices, and government facilities.
- Mul-T-Lock — Best for clients who prioritize physical attack resistance. Common in high-value storage, data centers, and commercial retail.
- Abloy — Best for clients who need the highest available pick resistance and are willing to pay a premium. Common in critical infrastructure, embassies, and high-security institutional settings.
All three are appropriate replacements for standard cylinders in any application where key control or attack resistance is a genuine concern. A property manager who has had security incidents, a law firm with sensitive client files, or a school district managing master key access across a campus are all appropriate candidates for a high-security cylinder recommendation.
The Locksmith's Role in High-Security Sales
Selling high-security hardware requires a different conversation than a standard rekey or hardware replacement:
- Establish the threat. What specifically is the client concerned about? Unauthorized key duplication? Physical break-in? Internal access control? The answer determines which high-security features are relevant.
- Explain the mechanism. Clients who understand why Medeco's angled pins or Abloy's disc detainer make their lock more secure are far more likely to approve the investment than clients who hear only "it's more secure."
- Document the key control. For restricted keyway installations, document the key control agreement, the authorized duplication channels, and the initial key issuance in the client's file. This documentation is part of the service you are providing.
- Schedule ongoing service. High-security accounts are recurring accounts. Annual inspection, key audit, and issuance record review are all billable services that high-security clients expect.