The Mathematics of Safe Combinations

18/07/2018

Many modern safes are secured by a combination lock. The safe will only open when the ‘combination’ – the correct sequence of numbers – is entered. Methods of entering the numbers differ between safes. Two examples you might be familiar with are the old-fashioned ‘dial’ and modern numerical keypad. Both rely on the owner of the safe remembering the combination!

Combination or Permutation?

Strictly speaking, a combination lock isn’t a combination lock at all. In mathematics, a ‘combination’ is a sequence of numbers where the order is irrelevant. When the order of the number matters, the sequence is known as a ‘permutation’. If the combination of your lock is 123 and you enter 321, the safe remains locked. So, it is not really a combination lock at all. It’s an interesting side note, but we think it’s too late to introduce the term ‘permutation lock’ so we’re stuck with the inaccurate terminology for now. 

The Best Combinations 

There are many different techniques you can use to create and remember your combination. A simple technique you can use is to start with a predictable and memorable date e.g. your date of birth. You should then make unpredictable changes to this, such as adding 1 to each digit or entering the digit above it on your keypad so 4=1, 5=2 etc. 

Some of the most common combinations people choose are the same number repeated. While this is easy to remember, it is also easy to guess and is not a good choice. If your code is so obscure that you have to write it down to memorise it, it’s not a good choice and your security has been compromised by the existence of that piece of paper. 

Forgotten Code?

While it might be your worst nightmare, forgetting your code isn’t the end of the world. Should you forget the digits to your safe, we are on hand to help. We are the only local locksmiths that use lock picks instead of drills to gain access to your safe and so far, we have never failed to open a lock – even working on some safes at our own expense. We even offer a 24-hour emergency call for all customers within Norfolk. Our customer service pledge allows us to achieve our high levels of work, which has seen us become Norfolk Trusted Traders. 

Need to regain access to your safe? We can help, give us a call on 01603 812613 or email us on admin@ptlockandsafe.co.uk.

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