When it comes to putting a lock on your door, you have literally thousands of different choices of brand, appearance, type, and cost, to choose from. Here we will discuss a few of the most common different types of door locks. If your needs are quite simple, and you just need a combination padlock for a locker, you can be looking at less than US$20. If you require the most high-tech keyless door locks then you can pay $1000 for a biometric solution. And then there's everything in between!
The door locks most people will be familiar with are bitted-key pin-tumbler door locks. These are a conventional lock, opened by inserting a key with a number of grooves etched into a face (called bittings) into the keyway of the lock, and turning. Simple. However, these locks are susceptible to picking - as all locks are to a greater or lesser degree - and for this reason some people may wish to avoid them. If you want sturdy door locks that will resist a determined effort, either by picking or a brute force attack, consider Schlage locks. They start at about $65.
If you do not want to worry about the inconvenience inherent with pin tumbler locks and their vulnerabilities then you will be looking into keyless door locks. The first main type of these are mechanical combination door locks. There are two main configurations for these, one being a push-button style keypad lock and the other being a dial-based combination lock. Certain brands and models of both of these types have their problems: The correct sequence for some of the dial combination locks can be "heard", if you know the right tricks, while the keypad locks have their own complement of problems, starting with public knowledge of their default combination. As with any keyless door locks if you do not have the ability to change the factory set combination you should probably avoid it. The cheapest combination door locks can be bought for as little as $15 and very good ones can cost in excess of $250.
Electronic door locks are the next main type. While there is an even wider range of lock types in this category, the four you are most likely to encounter are electronic combination door locks, biometric door locks, key card locks, and remote-controlled locks. Electronic combination door locks are often found on smaller, cheaper safes (as well as more expensive models, of course) which can be obtained for as little as $100. These have advantages over mechanical locks as they eliminate the possibilities of being able to exploit simple mechanical design faults of the lock itself. They do, of course, have their own unique set of problems and vulnerabilities, but, it requires a great deal of knowledge to be able to exploit them.
Biometric door locks scan a part of the human anatomy and record patterns obtained from the scan for later comparison. This usually takes the form of a retina or fingerprint scanner. While retina scanners remain expensive and out of reach for most consumers, biometric fingerprint locks have come down in price considerably lately and are widely available. They can be obtained for as little as $150 but you probably wish to spend more for reliability and a fuller feature set. Key card locks are usually used in conjunction with either of the previously mentioned electronic door locks as a convenient bypass.
The final main type of keyless door locks are remote controlled locks. They use a short range high frequency transmitter to send an encrypted open command to open power door locks. These are commonly seen on electronic gates, and garage roller doors.
