Rotational Cipher
Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.
The Caesar cipher is a simple shift cipher that relies on
transposing all the letters in the alphabet using an integer key
between 0
and 26
. Using a key of 0
or 26
will always yield
the same output due to modular arithmetic. The letter is shifted
for as many values as the value of the key.
The general notation for rotational ciphers is ROT + <key>
.
The most commonly used rotational cipher is ROT13
.
A ROT13
on the Latin alphabet would be as follows:
Plain: abcdefghijklmnopqrstuvwxyz
Cipher: nopqrstuvwxyzabcdefghijklm
It is stronger than the Atbash cipher because it has 27 possible keys, and 25 usable keys.
Ciphertext is written out in the same formatting as the input including spaces and punctuation.
Examples
- ROT5
omg
gives trl
- ROT0
c
gives c
- ROT26
Cool
gives Cool
- ROT13
The quick brown fox jumps over the lazy dog.
gives Gur dhvpx oebja sbk whzcf bire gur ynml qbt.
- ROT13
Gur dhvpx oebja sbk whzcf bire gur ynml qbt.
gives The quick brown fox jumps over the lazy dog.
Running the tests
To run the tests run the command go test
from within the exercise directory.
If the test suite contains benchmarks, you can run these with the -bench
flag:
go test -bench .
Keep in mind that each reviewer will run benchmarks on a different machine, with
different specs, so the results from these benchmark tests may vary.
For more detailed information about the Go track, including how to get help if
you're having trouble, please visit the exercism.io Go language page.
Source
Wikipedia https://en.wikipedia.org/wiki/Caesar_cipher
Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.