module SecureAttribute

# File lib/secure_attribute.rb, line 14
def self.decipher(data, key)
  algorithm, iv, data = SecureAttribute.unpack(data)
  SecureAttribute.decrypt(algorithm, data, key, iv)
end

# File lib/secure_attribute.rb, line 26
def self.decrypt(algorithm, data, key, iv)
  cipher = OpenSSL::Cipher.new(algorithm).decrypt
  cipher.key, cipher.iv = key, iv
  decrypted = cipher.update(data)
  decrypted << cipher.final
end

# File lib/secure_attribute.rb, line 9
def self.encipher(algorithm, data, key)
  encrypted, iv = SecureAttribute.encrypt(algorithm, data, key)
  SecureAttribute.pack(algorithm, iv, encrypted)
end

# File lib/secure_attribute.rb, line 19
def self.encrypt(algorithm, data, key)
  cipher = OpenSSL::Cipher.new(algorithm).encrypt
  cipher.key = key
  iv = cipher.random_iv
  [cipher.update(data) + cipher.final, iv]
end

# File lib/secure_attribute.rb, line 42
def self.export_random_key_base64(algorithm)
  Base64.strict_encode64(OpenSSL::Cipher.new(algorithm).random_key)
end

# File lib/secure_attribute.rb, line 5
def self.included(model)
  model.extend(ClassMethods)
end

# File lib/secure_attribute.rb, line 33
def self.pack(algorithm, iv, encrypted)
  ["", algorithm, Base64.strict_encode64(iv), Base64.strict_encode64(encrypted)].join("$")
end

# File lib/secure_attribute.rb, line 37
def self.unpack(string)
  _, algorithm, iv, data = string.split("$")
  [algorithm, Base64.decode64(iv), Base64.decode64(data)]
end