npm install cipher.jsThis library is an attempt at not cheating the UK National Cipher Challenge, whilst also serving a purpose to the open source community. (That was a joke; I would only ever think about myself)
(Have a play-a-round on Codepen)
encrypt, decrypt and tools. These are all stored in the object cipher. So, if I wanted to get to the tools section, I would do: cipher.tools.BLAH.#### caesar(str, amount)
This takes two arguments - str and amount. str is the phrase that you want to be encrypted, and amount is a number of letters to shift. Example:
``
cipher.encrypt.caesar('abc', 1) // Returns 'bcd'
var secretMessage = cipher.encrypt.caesar('Momma, I just killed a man-', 13);
console.log(secretMessage) // Logs 'Zbzzn, V whfg xvyyrq n zna-'
`
#### reverseString(str, spaces)
This too takes two arguments - str and spaces. str is the phrase you want to be reversed, whilst spaces is a boolean. If true, the str will be reversed including spaces. If false, it will disregard all spaces and reverse it that way. Example:`
cipher.encrypt.reverseString('abc def', true); // returns 'def abc'
cipher.encrypt.reverseString('abc def', false); // returns 'defabc'
a lot.#### caesar(str, amount)
However visually symmetrical to the
cipher.encrypt.caesar, it has one difference. Instead of moving the letters forward by the amount, it moves them backwards. Example:
`
cipher.decrypt.caesar('abc', 1) // returns 'zab'
var decodedMessage = cipher.decrypt.caesar('Zbzzn, V whfg xvyyrq n zna-', 13);
console.log(decodedMessage) // Logs 'Momma, I just killed a man-'
#### caesarGuess(str, letter)
This is my favourite bit of the library. It can take any string (the second argument isn't required) and guess a shift, then decode it into English.
To understand its use, you need to know how it works. These are the steps it follows:
- Find the most common letter, using a call to the
.
- Work out the difference between it and the most common letters in English (e,a,t,o).
- Store these in an object.
- Decrypt the text using the cipher.decrypt.caesar() function using an amount of the chosen letter.
- Display result.Usually it works when
letter is 'e', because it's the mostest most common letter in English. Examples:
`
var words = 'Hello! this is a very large piece of text containing a lot of vowels. Hey, look at that I\'m using e so much. I like e. Did you know that in mathematics e^n is a transcendental number?'
var secretMessage = cipher.encrypt.caesar(words,18)
cipher.decrypt.caesarGuess(secretMessage); // Returns what is the same as the words variable.
#### reverseString(str, spaces)
This is 100% the same as the
function. Scroll up to read the documentation for that.$3
These do not encrypt or decrypt, but are common resuable bits of code.#### alphabetNum(letter)
This function takes one argument - letter - and returns the number of that letter in the alphabet. Examples:
`
cipher.tools.alphabetNum('a') // Returns 1.
#### stringNum(str)
This function does the same as the
, but instead turns a string into an array of numbers corresponding to the letters at that point. Examples:
`
cipher.tools.stringNum('abc') // Returns ['1','2','3']
#### frequency(str)
This function returns an object of information about a given string. In total, it returns 5 things.
cipher.tools.frequency(str) // Returns
{
consisency: // Equal to (range*str.length)/100 - the higher the number the more 'diverse' a string is. Used to check if // its been encrypted with a shift cipher.
mostUsedLetter: // Funnily enough, the most used letter.
maxAmountOfTimesALetterAppeared: // Have a guess.
minAmountOfTimesALetterAppeared: // "" ""
range: // The range of the amount of times letters occured. If 'a' had been used 3 times and 'b' had been used once, the
// range would be 2 (3-1).
}