![shift cipher shift cipher](https://i.ytimg.com/vi/WATHdJR2Nas/hqdefault.jpg)
Again, once you figure out a single word you'll know the shift and the rest are easy. E, R, S, T are all fairly common, so if you see an often repeated cipher text letter it's probably one of these. They may only need to try it on a few words, once a couple work out then they know the shift to use for the rest.Ī breaker can also use a technique called frequency analysis - each letter in the English alphabet has a frequency of usage, or likeliness to show up.
![shift cipher shift cipher](https://i.ytimg.com/vi/F6vBdvt8Ctw/maxresdefault.jpg)
Shift cipher code#
So, a code breaker could rather easily use a brute force approach and try all 25 combinations. The weakness of this cipher is that using an English alphabet there are only 25 combinations (26 letters in the English alphabet minus the actual proper one) for each cipher text value. To decode this, the solver would take their cipher wheel, and it has to be the same type of wheel the cipher was created on, set the wheel to the key, then look up each cipher text letter on the inner ring and write down it's plain text match. If you embed the key in the code, you could have an accepted rule that the decoder knows such as "the first two letter are always the plain text/cipher text key", or use the last two letters, or letters 5 and 6. The only important part is that the recipient of the code knows the key, or the key is embedded in the code. Of course you can use any combination of plain text value to cipher text value as your key.
![shift cipher shift cipher](https://2.bp.blogspot.com/-r4ZXLbVBLUQ/WDJLw7fkLxI/AAAAAAAAAXA/AD0lmt1JwEom4qnikkVa9b40pCS0xWMZACLcB/s1600/Shift.png)
On any of my cipher wheels, you would simply say that the key is the capital A (on the outer ring) equals lowercase g (on the inner ring), set the cipher wheel to that then look up each plain text value on the outer ring and write down it's match on the inner ring. This is called a shift cipher as it simply shifts the cipher text alphabet under the plain text some number of characters. The easiest form of cipher to create (and unfortunately the easiest to crack) is the basic shift cipher.