Precautions for Use of the Master Lock Key Storage Lock
and Lockboxes from other Manufacturers
Some of this information applies specifically to the Master Key Storage Lock and some applies to lockboxes in general.

The Master Key Storage Lock is advertised as a safe place to store keys. The packaging shows a young girl with a backpack retrieving keys from the storage lock (see above, at the right,) presumably to unlock the family home and go inside after school while the adults are away at work. Other suggested uses are for allowing contractors to enter, and as a safe alternative to hiding keys.

Aside from being vulnerable to the "feeler gauge" and "visual" methods of recovering the combination, the lock is vulnerable to user error. After the lock is closed, the user must scramble the dials (or set the dials to some preset number, such as 0000.) If the user forgets to turn the dials, the lock can be opened just by pushing down the lever. Young children are likely to forget to scramble the dials. After a child has entered the home, a burglar could make a note of the combination for use later when the house is empty, even after the dials have been scrambled by an adult.

A second vulnerability is the users may choose a combination that is "easy to remember," but, unfortunately, also easy to guess. If young children are to open the lock, the parents may choose a combination that will be easy for the children to remember.

However, the lockbox does provide an added level of security over just hiding the keys. Therefore, we recommend, for this lockbox, as well as lockboxes from other manufacturers:

Use the lockbox only to store a key for use in an emergency lockout situation.

Store just one key, the one to open the house. Other keys may be hidden in the house.
(Otherwise, a car thief may drive off in your Mercedes or Porsche, parked out front, without even entering your house.)

Do not mount the lockbox in plain view, as shown on the package (see above) and on Master Lock's website. Instead, secure the lockbox in a hidden location, well away from the door that its stored key unlocks. It is best that a burglar not know that there is a lockbox, even if the lockbox is very secure. Furthermore, the lockbox should not be hidden where a burglar might look for hidden keys. However, also look out for the safety of the people who need to retrieve keys. Don't mount the lockbox in a location where a predator might hide, such as behind dense shrubbery.

You may mount the lockbox at the home of a relative or close friend, at least several blocks away. The burglar may get the box open, but then not know which house opens using the key inside. Again, the lockbox should still be used for emergency purposes only, so the burglar doesn't observe people retrieving the key and following them to see which door it opens. The lockbox installed at the other house can be more accessible, but should not be in plain view.

How this lockbox and lockboxes from other manufacturers might be redesigned for added security:

1) The combination should "clear" (reset) automatically when the lockbox is closed. We suggest that the dials return to 0000.

2) The lockbox design should prevent the "feeler gauge," "visual" and other methods from opening the lock.

Our internet search located other thumbwheel lockboxes. None of them had automatic combination clearing. There is also a 10 button pushbutton lockbox, which does clear. However, this lockbox appears to have only 1024 possible combinations, far less than the 10,000 on the thumbwheel lockboxes, and a small enough number to permit trying them all within a "reasonable" time.

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