How do I decrypt a file in Rails? - ruby-on-rails

Question

Wow, what a vague quesetion, I know. I have a file called enc_file in my Rails repo.
In my environments/production.rb, I have:
authentication_file = "#{Rails.root}/enc_file"
unless File.exist?(authentication_file)
puts "ERROR: File not found! (#{authentication_file})"
raise SystemExit, 1
end
my_config = YAML.load(PaymentGatewayCipher.decrypt(authentication_file)).symbolize_keys!
config.app_config.pay_pal.merge!(pay_pal_config.slice(:login, :password, :business, :business_id, :cert_id, :private_key, :signature).merge(
:return_to_merchant => false,
:server => 'whatever.paypal.com'
))
Then in my payment_gateway_cipher.rb file, I have:
require 'openssl'
# Encapsulates payment gateway encryption / decryption utility functions
class PaymentGatewayCipher
class << self
def encrypt(file, options = {})
cipher = create_cipher
cipher.encrypt(cipher_key)
data = cipher.update(File.read(file))
data << cipher.final
if to_file = options[:to]
# Write it out to a different file
File.open(to_file, 'wb') do |f|
f << data
end
end
data
end
# Decrypts the given file
def decrypt(file)
cipher = create_cipher
cipher.decrypt(cipher_key)
encrypted_data = File.open(file, 'rb') {|io| io.read}
data = cipher.update(encrypted_data)
data << cipher.final
end
# Generates the cipher to be used for encryption/decryption
def create_cipher
OpenSSL::Cipher::Cipher.new('aes-256-cbc')
end
# Loads the cipher key used for the symmetric algorithm
def cipher_key
File.open(File.join(Rails.root, 'config/mystuff/live/cipher.key'), 'rb') {|io| io.read}
end
end
end
How would I decrypt the enc_file to see it's content outside of Rails? I want to view the contents, modify them, and resave the file if possible.
Thoughts?

Answer 1

You have the decrypt function right there, so presumably by outputting the result of that function?
puts decrypt("path/to/enc_file")
Or writing the same to a file which you can then view outside of Ruby:
File.open("decrypted_file", "w") do |f|
f.write decrypt("path/to/enc_file")
end