With every possession comes a natural urge to protect it with all the might, protect it with every possible barrier that he could invent. One of the last bulwarks to this line of security has been the simple yet efficient, padlock. Padlocks were one of the very first mechanical inventions that were designed to protect the assets and houses. A very high degree of key specificity makes the chances of having one key working with more than one lock highly unlikely. In order to use it, there is no complicated mechanism unlike setting a password of 6 characters or more and then always remembering them, but a simple key. All one has to do is to insert appropriate key to engage or release the lock. Simple enough? But is it really that simple from the inside? Let’s find out. Why does every lock has its own unique key?