Comparing Safe Deposit Boxes

Over the last two centuries, safe deposit boxes have faced the constant challenge of having their locks damaged or compromised by thieves. Configurations of safe deposit boxes once included combination key and dial locks with a number of dials on top. These dials had to be turned to the correct sequence before a key could be inserted. Today, manual key locks are common and electronic and other methods are used to enhance security.

Antique Safe Deposit Boxes

In the days when keys had only a few notches, added security was provided for safe deposit boxes through combination locks. An example of how the boxes worked can be explained with the Swiss bank deposit boxes.

In the 1920s, combination locks contained two key slots. Each combination lock had 22 letters, but this still allowed for over 225,000 possible sequences. The bank representative inserted his key first, and then would leave the room. The customer would dial in the proper sequence on the combination locks. When the second key cover opened, the customer would put the key into it and unlock the box.

As with all combination locks, problems arose when the customer could not recall the precise sequence of the letter code, or even in which order to enter it on the dials. Combination locks quickly evolved to a single dial on which multiple numbers could be entered in a left-right turn sequence.

Modern Safe Deposit Box Features

Bank safe deposit boxes used commonly today have four key slots and no dials. One key slot is for the bank's key, the second for the customer's. 

The other two key slots are blocked with a colored plastic T-shaped insert to obstruct users from inserting keys in error. These safe deposit boxes can be issued 3 times to new customers without requiring adjustment of the key tumblers to a new combination.


Small bank safe deposit boxes, about the size of a wall mailbox, have just 2 key slots, for the bank's and customer's keys. These are altered every time the bank safe deposit box is emptied and rented to a new client.

Electronic and Fingerprint Security - The Future of Bank Safe Deposit Boxes

The future of boxes lies in banks looking to issuing electronic passcard for locks for safe deposit boxes. They will allow customers to retain a mechanical key lock, as the bank's guard key. Fingerprint-based security may also become common on safe deposit boxes, as well as electronic keypad locks, which would be password-based. These would greatly reduce loss and damage to metal keys.

Safe deposit box vaults may also be located outside of the central vault area to improve the security of the bank's general operations. Building construction now allows for floors sturdy enough to support the weight of secure vaults above the basement. In areas which flood frequently, large bank offices could move all their secure vaults well above ground level.

Because the purpose of a bank safe deposit box is to protect its contents, security systems will continue to evolve to enhance the protection of the boxes themselves.

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