A Technical Analysis of Bumping © 2006 Marc Weber Tobias and Investigative Law Offices Document 060922107 OPENING LOCKS BY BUMPING IN FIVE SECONDS OR LESS: IS IT REALLY A THREAT TO PHYSICAL SECURITY? A TECHNICAL ANALYSIS OF THE ISSUES Released on April 4, 2006 on http://www.security.org © 2006 Marc Weber Tobias, Investigative Law Offices The information contained in this report appears as part of a comprehensive treatment of bumping in the 2006 version of LSS+, the Multimedia Edition of Locks, Safes and Security by the same author. Appreciation is expressed to Barry Wels and Han Fey for their technical input and assistance in developing certain materials for this document. Our office is consulting with manufacturers to develop standards for testing cylinders against bumping. Currently, testing laboratories are not adequately addressing this issue. Videos that demonstrate the vulnerability of public and private mailbox locks are available to law enforcement agencies. The author may be contacted at +1.605.334.1155 or
[email protected]. Many standard five and six pin tumbler locks can be opened rapidly through a technique known as bumping with a key similar to that shown above. Some high security locks can also be opened with this technique. These diagrams show how the bump key operates in a pin tumbler lock. One technique requires that the key (left) be withdrawn by one tumbler position and then slammed into the lock. This will cause the top pins (right) to bounce and separate from the bottom pins, thereby creating a gap at the shear line that will allow the plug to turn.