Caesar Cypher

Mix.install([
  {:kino, github: "livebook-dev/kino", override: true},
  {:kino_lab, "~> 0.1.0-dev", github: "jonatanklosko/kino_lab"},
  {:vega_lite, "~> 0.1.4"},
  {:kino_vega_lite, "~> 0.1.1"},
  {:benchee, "~> 0.1"},
  {:ecto, "~> 3.7"},
  {:math, "~> 0.7.0"},
  {:faker, "~> 0.17.0"},
  {:utils, path: "#{__DIR__}/../utils"},
  {:tested_cell, git: "https://github.com/BrooklinJazz/tested_cell"}
])

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Caesar Cypher

A cypher alters characters in order to make secret messages. The Caesar cypher is a substitution cypher named after the Roman emperor Julius Caesar.

Typically caesar cyphers use a key to shift letters. For example, a caesar cypher with a key of 1 would shift each letter by one.

CaesarCypher.encode("abcdefghijklmnopqrstuvwyxz", 1)
"bcdefghijklmnopqrstuvwyxza"

A key of 2 would shift each letter by two.

CaesarCypher.encode("abcdefghijklmnopqrstuvwyxz", 2)
"cdefghijklmnopqrstuvwyxzab"

Ensure you handle keys between 1 and 25.

CaesarCypher.encode("abcdefghijklmnopqrstuvwyxz", 25)
"zabcdefghijklmnopqrstuvwyx"

CaesarCypher should also be able to decode messages given the key.

CaesarCypher.decode("cdefghijklmnopqrstuvwyxzab", 2)
"abcdefghijklmnopqrstuvwyxz"

The cypher should only handle lowercase letters and ignore non-alphabetical characters.

CaesarCypher.encode("et tu, brute?", 2)
"gv vw, dtwvg?"

Enter your solution below.

defmodule CaesarCypher do
  def encode(string, key) do
  end

  def decode(string, key) do
  end
end

Utils.feedback(:caesar_cypher, CaesarCypher)

Commit Your Progress

Run the following in your command line from the project folder to track and save your progress in a Git commit.

$ git add .
$ git commit -m "finish caesar cypher exercise"