AES Encryption for Ruby 1.9

aes_crypt.rb

require 'openssl'

module AESCrypt
  # Decrypts a block of data (encrypted_data) given an encryption key
  # and an initialization vector (iv).  Keys, iv's, and the data
  # returned are all binary strings.  Cipher_type should be
  # "AES-256-CBC", "AES-256-ECB", or any of the cipher types
  # supported by OpenSSL.  Pass nil for the iv if the encryption type
  # doesn't use iv's (like ECB).
  #:return: => String
  #:arg: encrypted_data => String
  #:arg: key => String
  #:arg: iv => String
  #:arg: cipher_type => String
  def AESCrypt.decrypt(encrypted_data, key, iv, cipher_type)
    aes = OpenSSL::Cipher::Cipher.new(cipher_type)
    aes.decrypt
    aes.key = key
    aes.iv = iv if iv != nil
    aes.update([encrypted_data].pack("H*")) + aes.final
  end

  # Encrypts a block of data given an encryption key and an
  # initialization vector (iv).  Keys, iv's, and the data returned
  # are all binary strings.  Cipher_type should be "AES-256-CBC",
  # "AES-256-ECB", or any of the cipher types supported by OpenSSL.
  # Pass nil for the iv if the encryption type doesn't use iv's (like
  # ECB).
  #:return: => String
  #:arg: data => String
  #:arg: key => String
  #:arg: iv => String
  #:arg: cipher_type => String
  def AESCrypt.encrypt(data, key, iv, cipher_type)
    aes = OpenSSL::Cipher::Cipher.new(cipher_type)
    aes.encrypt
    aes.key = key
    aes.iv = iv if iv != nil
    (aes.update(data) + aes.final).unpack("H*")[0]
  end
end

# And use thusly:

AESCrypt.encrypt(string, "mykey", nil, "AES-256-CBC")
AESCrypt.decrypt(string, "mykey", nil, "AES-256-CBC")

@watsoncj key = OpenSSL::Digest::SHA256.new("p4ssw0rd").digest