[Ruby] A simple example of AES encryption in Ruby

encryption.rb

# encoding: utf-8

require "openssl"
require "base64"

CIPHER_ALGO = "AES-256-CBC"
SALT_SIZE = 8

def encrypt(data, pass)
  salt = OpenSSL::Random.random_bytes(SALT_SIZE)
  cipher = OpenSSL::Cipher::Cipher.new(CIPHER_ALGO)
  cipher.encrypt
  cipher.pkcs5_keyivgen(pass, salt, 1)
  enc_data = cipher.update(data) + cipher.final
  salt + enc_data
end

def decrypt(enc_data, pass)
  enc_data = enc_data.dup
  enc_data.force_encoding("ASCII-8BIT")
  salt = enc_data[0, SALT_SIZE]
  data = enc_data[SALT_SIZE..-1]
  cipher = OpenSSL::Cipher::Cipher.new(CIPHER_ALGO)
  cipher.decrypt
  cipher.pkcs5_keyivgen(pass, salt, 1)
  cipher.update(data) + cipher.final
end

pass = "foobar"
data = "ひみつ"

enc = encrypt(data, pass)
puts Base64.strict_encode64(enc)

dec = decrypt(enc, pass)
puts dec