How-to · Updated 2026

What Is a Cipher Lock?

A cipher lock is a fully mechanical push-button combination lock - no battery, no wiring, and on most models no key at all - that opens when you press the correct sequence of numbered buttons. You'll also see it called a cypher lock or, most often in the trade, a Simplex lock, after the dormakaba Simplex line that's been the standard since the 1960s. They're the lock on the office supply closet, the school staff entrance, the utility room, and the gate that a dozen different people need to open without anyone carrying a key. A genuine commercial-grade unit like the Simplex L1000 runs roughly $430-480; a lighter residential version for a house door runs $150-230.

How a cipher lock works

A cipher lock has a small bank of numbered push-buttons built into the lock body itself - usually five. There's one shared combination for the whole door, and the five-button mechanism gives well over a thousand possible combinations - the original Simplex mechanism was marketed on more than 1,000 - using anywhere from one to all five buttons: press them individually in sequence, or press two or more at once as a single step. Enter the correct sequence and the lever turns; get it wrong and it doesn't.

The whole thing is mechanical. There's no battery to die, no wiring to run, and no circuit board to fail - it's a purely physical arrangement of pins and cams behind the buttons, the same basic idea as a bicycle combination lock scaled up into a door lockset. That's also why it's weatherproof by nature and why it keeps working through a power outage, which is a big part of why it's survived essentially unchanged since the 1960s.

Changing the code is a maintenance task, not something you do from the keypad on the fly - it needs a control key and a small internal reset (see the steps below). And critically, the push-button code only controls entry from outside. The inside lever or knob turns freely at all times - the "free egress" feature every cipher lock is built around, so anyone inside can always walk out without touching a button, code, or key.

Why they're called cipher locks (and Simplex locks)

"Cipher lock" describes what the mechanism does - the buttons form a numeric cipher, or code, that has to be entered correctly - and it's the generic, mechanism-neutral term used across security and government writing. "Simplex" is a brand name that became the generic term the way "Kleenex" or "Xerox" did, because for decades there was really only one lock like this on the market.

The mechanism traces back to a push-button filing-cabinet lock built by Simplex Security Systems in New York, offering more than 1,000 combinations from five buttons. In 1960, Bell Canada wanted an equivalent for doors instead of file drawers; Aaron Fish adapted the Simplex mechanism into a door lockset, and the first Unican push-button door locks shipped to Bell Canada in 1964. Unican was later folded into what's now dormakaba, which still sells the direct descendant of that 1964 design as the Simplex L1000 and 1000 series - why "Simplex" and "cipher lock" get used interchangeably, even though Simplex is technically one manufacturer's line.

Where cipher locks make sense

Cipher locks show up wherever a group of people - not just one household - needs through a door without keys changing hands: office supply rooms and back-of-house doors, school staff entrances, utility and mechanical rooms, server closets, gates, and commercial or institutional buildings that would otherwise be cutting new keys every time someone leaves. Government and military facilities use them for the same reason: nobody has to collect a key from a departing employee, because there's no key to collect - you just change the code. It's also the core commercial pitch dormakaba makes for the Simplex line: it eliminates the cost of issuing, tracking, and collecting keys or cards for a door many people share.

Cipher lock vs electronic keypad vs smart lock

A cipher lock, an electronic keypad deadbolt, and a smart lock all put a code on a door, but they solve different problems. A cipher lock like the Simplex L1000 is 100% mechanical - one shared code, no batteries, no electronics, and it keeps working through a power cut. An electronic keypad deadbolt, like our residential roundup's Schlage BE365 pick, runs on a 9-volt battery but can store separate per-person codes instead of one shared one. A smart lock, like the picks in our smart-lock roundup, adds an app, remote locking, and activity logs on top of that, at the cost of needing power and connectivity. Want zero batteries and don't care who used the door and when? Stay mechanical. Want individual codes, logs, or remote access? Go electronic.

Are cipher locks secure?

Reasonably, for what they're designed to do - with one structural trade-off. Because there's a single shared code, security depends on who knows it and how carefully it's guarded: shoulder-surfing, a worn or shinier-looking button, or someone passing the code to a person who shouldn't have it are the real risks, not lockpicking. A commercial-grade unit like the Simplex L1000 is built to institutional spec - dormakaba lists it as DoD 5220.22-M compliant, with a 3-hour UL/ULC fire rating on labeled doors - and the keyless version has no pin-tumbler cylinder, so there's nothing for a bump key or pick set to work on. A key-override model like the Simplex 3000 reintroduces a normal key cylinder for backup access, and with it the ordinary risk of that cylinder being picked or bumped. The discipline that actually matters in practice: rotate the code periodically, and whenever someone with access leaves.

What a cipher lock costs

A genuine commercial mechanical pushbutton lock isn't cheap: the Simplex L1000 runs roughly $430-480, and the narrow-stile Simplex 3000 (for glass storefront doors) runs about $240-310, before installation. dormakaba doesn't publish a flat retail price - like most commercial door hardware, these are sold through locksmith and door-hardware distributors and typically quoted or installed per door. General locksmith keypad-lock installation runs roughly $100-350 including hardware for a simpler job; see our locksmith cost guide and rekey cost guide for the broader range of what locksmiths charge. For a house front door, the residential Lockey M210 below gets you the same idea for a fraction of the price.

How to change the code on a cipher lock

The exact procedure is specific to the model, so the steps below are for the dormakaba Simplex 1000/L1000 series - the lock most people picture when they say "cipher lock" - and are summarized from dormakaba's own change-the-code instructions, linked in the sources. Do it with the door open so a mistake can't lock you out. A different lock, like the residential Lockey M210 below, uses an entirely different mechanism (see its own instructions) - don't apply these steps to a different lock.

What we recommend

The classic cipher lock

Kaba Simplex L1000 (LL1011-26D-41)

$463.65 as of Oct 12, 2026 09:00 UTC

This is the lock most people mean when they say "cipher lock" - the direct descendant of the original 1960s Simplex/Unican mechanism, still sold by dormakaba today. It's DoD 5220.22-M compliant with a 3-hour UL/ULC fire rating on labeled doors, fully mechanical with more than 1,000 possible code combinations from its five buttons, and has no key cylinder at all on this SKU, so there's nothing to pick or bump. It's genuinely commercial-grade hardware, not a residential product wearing a commercial label, which is reflected in the price.

Pros

• + DoD 5220.22-M compliant, with a 3-hour UL/ULC fire rating on labeled doors
• + More than 1,000 possible combinations, changeable in the field
• + No key cylinder on this SKU - nothing to pick or bump
• + 100% mechanical - keeps working through a power outage

Cons

• – No key override - a key-override LL1021 version exists as a separate SKU
• – Commercial pricing - more than a residential keypad deadbolt
• – One shared code for the whole door, not per-person codes

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For glass storefront doors, with a key backup

Kaba Simplex 3001-26D-41 Narrow Stile Lock

$262.24 as of Oct 12, 2026 09:00 UTC

The pick for a narrow-stile aluminum-and-glass storefront or office entrance, which the Simplex L1000's cylindrical lever body isn't built for. It adds a key-override cylinder and an inside thumbturn alongside the push-button code, so a manager or locksmith can always get in with a key if the combination is forgotten - the "dual access" version of the same mechanical idea.

Pros

• + Fits narrow-stile glass/aluminum storefront doors the L1000 can't
• + Key override plus combination - two ways in, not just one
• + Free-egress passage/lockout functions built in
• + Still 100% mechanical - no batteries or wiring

Cons

• – Key cylinder is a normal pickable/bumpable point, unlike the keyless L1000
• – Narrow-stile glass doors only, not a standard wood or steel door
• – Sold through commercial distributors, not big-box retail

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Same idea for a house door

Lockey M210 EZ Mechanical Keyless Deadbolt

$137.07 as of Oct 12, 2026 09:00 UTC

If what you actually want is the cipher-lock idea - no batteries, no key, one shared code - on an ordinary house front door, this is it. It's a 100% mechanical push-button deadbolt with no key cylinder at all, at a fraction of the price of commercial hardware. It's residential-duty hardware rather than the L1000's institutional-spec hardware, and, like the L1000, it gives everyone in the house the same one code rather than individual codes.

Pros

• + Genuinely no batteries or wiring - nothing to die, ever
• + Fully keyless - no key cylinder to pick or bump
• + Far cheaper than commercial cipher-lock hardware
• + Lifetime mechanical warranty from Lockey

Cons

• – Residential-duty hardware - not built to the L1000's institutional spec
• – One shared code for the household, not per-person codes
• – No key backup - a forgotten code means reprogramming or a locksmith

Check price on Amazon →

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