A detailed technical analysis prepared by Marc Weber Tobias

Bumping of Locks: Legal issues in the United States

IEEE on HOPE 2006, July 26, 2006

NEWSWEEK MAGAZINE, August 2, 2006, “Bumping”

A report was released on March 22, 2006 in the Netherlands regarding the vulnerability from bumping of more than 80 different pin tumbler locks that are manufactured or utilized in that country. The findings were researched and produced by Dutch Consumentenbond, the most prestigious Dutch consumer protection organization . This study was largely the result of significant research that was conducted by Toool, “The Open Organization of Lock pickers” in the Netherlands with regard to the vulnerability of certain cylinders. Their tests and that of Consumentenbond demonstrated that many locks could be opened within seconds by an unskilled individual with less than one hour of instruction.  

The author previously addressed this issue in LSS+, the multimedia edition of Locks, Safes and Security, and in an article published in the ALOA magazine KEYNOTES in January, 2005. A White Paper had also been issued by members of Toool. Although the Netherlands tests showed that many locks could easily be opened with little skill, there are many variables that can affect the ability to compromise a lock in this manner. As a result, a detailed analysis of the threat level to physical security posed by bumping is now available.


An investigation by the author has determined that millions of public and private rented postal boxes are at risk because they can be easily opened with a bump key. The Postal Service has used the same five-pin tumbler lock for many years in its rented boxes that are located in post offices throughout the country and on military bases. Although these locks employ a restricted keyway that is only to be used by the post office, we found that blanks are commercially available that can easily be made into bump keys. We were able to purchase post office locks and keys on the Internet without any difficulty. Further, any post office patron can obtain as many original keys as needed for their rented box, thus the supply of original blanks for bump keys cannot be prevented. A video demonstration and briefing is available to law enforcement agencies.

There is a significant problem with theft of mail. Bump keys combined with twenty-four access to most post offices may exacerbate the problem and make it easier to target specific individuals or businesses for mail theft or interception. Many high profile individuals as well as corporations utilize box addresses, believing that they are more secure and that they have insulated themselves from surveillance, invasion of privacy, harassment or identity theft issues. The ability to target a mailing address and access mail through the use of a bump key is, in the view of the author, a serious threat which needs to be addressed and which will surely focus attention on bumping as a bypass technique. 

In some cities, thieves have already obtained keys to fit postal collection boxes. These same keys allow entry into apartment complexes, potentially placing all residents and their mail at risk. The Postal Service has already taken steps to deter this practice. Unless all public and private mail delivery boxes utilize bump-resistant locks, this threat is likely to increase. Higher security locks should be offered to all box rental patrons who are concerned about the threat from bumping.

UPS also offers private mail boxes in thousands of locations throughout the world as a result of their acquisition of Mail Boxes Etc. (MBE). These boxes are secured by locks that cost about one dollar to manufacture in Asia. Although several different keyways are used throughout the system, the vast majority of these locks can be opened in seconds with a bump key or other means. Blanks are readily available from commercial vendors and are easily cut. Many UPS mail locations offer 24 hour access. In the facilities that we examined, there was no real security against unauthorized entry to boxes by thieves. You may contact the author for further details at


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