Keycard lock

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In the 1970s, the lodging industry had an increasing problem with hotel crime. It was common that hotel room keys, even master keys, were sold on the street with tags identifying hotel and room number. Furthermore, these locks had few key variations and were easy to copy. The result was increasing problems with hotel room thefts and even assaults on hotel guests. As a consequence, the industry was looking for a new type of lock, where the key could be changed for every new guest.

It is important to trace the means adopted to make the locks secure. There have been several mechanical principles to by which security in key operated locks is obtained. One employs one or more moveable detainers which must be arranged in pre-selected positions by the key before the bolt will move. This principle was the base for the first known card operated lock, the VingCard®, invented by Tor Sørnes. This was a mechanical type of lock operated by a plastic key card with a pattern of holes. There were 32 positions for possible hole locations, giving up to 2 raised to the power of 32 = 4.2 billion different keys. The key could easily be changed for each new guest by inserting a new key template in the lock that matched the new key (See US patent 4,149,394). The lock was first installed for testing in a hotel in 1977, the first US installation was at Peachtree Plaza Hotel, Atlanta, Georgia in 1979.

Early in the 1980s the key card lock was electrified with diodes that detected the holes. The next development was the introduction of the magnetic stripe card key, a version of which was also patented by Tor Sørnes for VingCard®. Still later, smart card versions were introduced.