What is Impressioning?

Impressioning is the process of generating a key for a lock entirely from scratch without disassembling the lock or having beforehand knowledge of the working key’s depths.  This process involves taking a key blank and making “impressions” on the blank.  These marks can then be used to gain knowledge of the lock’s pinning scheme and from there generate a working key.

Schlage D-Series Key-In-Knob lock impressioned

Impression marks generally have to be taken many times to form a working key.  However, taking impression marks can be done quickly and discreetly.  If one walks by a door on a daily basis, they can take impression marks within a matter of seconds and then proceed on their way to work more on their key later.  Depending on their skill level and the pinning of the lock, by the end of several days or weeks, they will likely have a working key, permitting them entry to that door at their convenience.  This technique is therefore very practical in the field of security auditing/penetration testing.

Impressioning should not be done in instances where a consumer has purchased a home and there is a door they do not have a key to.  In instances such as these, picking open and rekeying the lock to an entirely new key is preferable.  Rekeying the lock is generally much more cost-effective, and it eliminates anyone who still has the keys to that door from returning to illegally gain entry.

Impressioning is however beneficial in instances where a consumer has purchased a non-rekeyable padlock without keys (e.g. from a flea market or antique store).  It can also be a suitable alternative to lockpicking in some instances.

Not all locks can be impressioned, or are very difficult to impression.  Kwikset locks for example use pins that make it very difficult to create and observe impression marks.  However, if a Kwikset lock has been rekeyed with aftermarket pins, this will likely make the lock easier to impression.  Also, some high security ASSA locks utilize special tumblers that are designed to provide deceptive readings if someone attempts to impression one of these locks.

This skill takes a long time to learn, so the concern of a criminal learning this skill and using it to commit a burglary are minimal.  Generally, criminals gravitate toward the path of least resistance, such as looking under doormats for hidden keys, using bump keys, or gaining entry forcibly.  Also, the investment in tools and time would likely dissuade the common criminal.

A locksmith however, specializes in creating keys for locks and therefore is often willing to invest the time and effort in their craft to learn this skill.  I, personally have been working on learning this skill for a considerable amount of time, but the results are now showing.