Caesar Cipher code example
Example 1: python caesar cipher
def caesar_encrypt():
word = input('Enter the plain text: ')
c = ''
for i in word:
if (i == ' '):
c += ' '
else:
c += (chr(ord(i) + 3))
return c
def caesar_decrypt():
word = input('Enter the cipher text: ')
c = ''
for i in word:
if (i == ' '):
c += ' '
else:
c += (chr(ord(i) - 3))
return c
plain = 'hello'
cipher = caesar_encrypt(plain)
decipher = caesar_decrypt(cipher)
Example 2: caesar cipher
function caesarCipher(str, shift) {
const alphabetArr = "abcdefghijklmnopqrstuvwxyz".split("");
let res = "";
for (let i = 0; i < str.length; i++) {
const char = str[i];
const idx = alphabetArr.indexOf(char);
// if it is not a letter, don`t shift it
if (idx === -1) {
res += char;
continue;
}
// only 26 letters in alphabet, if > 26 it wraps around
const encodedIdx = (idx + shift) % 26;
res += alphabetArr[encodedIdx];
}
return res;
}
Example 3: Caesars Cipher
const rot13 = str => {
let decodedCipher = ''
// The number 65 represents A which also is the begining of our alphabets.
// The number 90 represents Z which also is the end of our alphabets.
// Space and any other non-alpha character is less than 65(A) and greater than 90(Z).
// Split and loop over every character
str.split('').forEach(character => {
// Get the integer or unicode for ever character which returns a number and store it in letterChar
const letterChar = character.charCodeAt()
// Check if number(letterChar) is less than 65(A) or greater than 90(Z)
// If true, return the number(letterChar) which means, it could be a non-alpha character
// If false, return the number(letterChar) + 13, which means it has shifted 13 places.
let unicode = letterChar < 65 || letterChar > 90 ? letterChar : letterChar + 13
// unicode minus 1 is greater or equal to 90(Z)
// Set unicode to equal unicode minus 1,
// we minus 1 cause unicode will give us the right operand instead of the left operand
// eg N + 13 will give us B instead of A, so,
// We substract the now(unicode-1) unicode from 90 to get the number left, then we add it to 65(A),
// Cause we start from begining after we've met the end
if((unicode - 1) >= 90) unicode = (((unicode - 1) - 90) + 65)
// Convert and add every character to cipher
decodedCipher += String.fromCharCode(unicode)
})
return decodedCipher;
}
rot13("GUR DHVPX OEBJA SBK WHZCF BIRE GUR YNML QBT.");
// With love @kouqhar