algorithms/algorithms/strings/caesar_cipher.py at master · lualgorithm/algorithms · GitHub

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"""

Julius Caesar protected his confidential information by encrypting it using a cipher.

Caesar's cipher shifts each letter by a number of letters. If the shift takes you

past the end of the alphabet, just rotate back to the front of the alphabet.

In the case of a rotation by 3, w, x, y and z would map to z, a, b and c.

Original alphabet: abcdefghijklmnopqrstuvwxyz

Alphabet rotated +3: defghijklmnopqrstuvwxyzabc

"""

def caesar_cipher(s, k):

result = ""

for char in s:

n = ord(char)

if 64 < n < 91:

n = ((n - 65 + k) % 26) + 65

if 96 < n < 123:

n = ((n - 97 + k) % 26) + 97

result = result + chr(n)

return result

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