Can't get PayPal Encrypted Website Payments to work in Rails

Question

Hi all,

I am having problems getting PayPal Encrypted Website payments to work on a Rails site.

I am getting two different error messages when posting to the PayPal URL - on my staging site, which uses the sandbox, I am getting:

The certificate has been removed. Please use a valid certificate.

Whereas on the production site, I get:

We were unable to decrypt the certificate id.

As far as I can tell they are set up identically, except that one uses the PayPal Sandbox public key, and the other uses the normal PayPal public key. I must be overlooking some detail but I have banging my head against this for a couple of days now.

I used the following commands to generate public and private keys:

openssl genrsa -out app_key.pem 1024

openssl req -new -key app_key.pem -x509 -days 365 -out app_cert.pem

Then I uploaded app_cert.pem to PayPal and put my cert ID into a file like this:

development:
  user: [email protected]
  action_url: https://www.sandbox.paypal.com/cgi-bin/webscr 
  paypal_cert_file: certs/paypal_sandbox_cert.pem
  app_cert_file: certs/app_cert.pem
  app_key_file: certs/app_key.pem
  cert_id: CBDFN7JXBM2ZQ
  secret: dfasdkjh3453

test:
  user: [email protected]
  action_url: https://www.sandbox.paypal.com/cgi-bin/webscr 
  paypal_cert_file: certs/paypal_sandbox_cert.pem
  app_cert_file: certs/app_cert.pem
  app_key_file: certs/app_key.pem
  cert_id: CBDFN7JXBM2ZQ
  secret: dfasdkjh3453

staging:
  user: [email protected]
  action_url: https://www.sandbox.paypal.com/cgi-bin/webscr 
  paypal_cert_file: certs/paypal_sandbox_cert.pem
  app_cert_file: certs/app_cert.pem
  app_key_file: certs/app_key.pem
  cert_id: CBDFN7JXBM2ZQ
  secret: dfasdkjh3453

production:
  user: [email protected]
  action_url: https://www.paypal.com/cgi-bin/webscr 
  paypal_cert_file: certs/paypal_cert.pem
  app_cert_file: certs/app_cert.pem
  app_key_file: certs/app_key.pem
  cert_id: QG2TTZZM9DUH6
  secret: dfasdkjh3453

Then I use the following code in my Cart model to encrypt the data:

class Cart < ActiveRecord::Base
  has_many :line_items, :dependent => :destroy

  PAYPAL_CERT_PEM = File.read("#{Rails.root}/#{PAYPAL_CONFIG[:paypal_cert_file]}")
  APP_CERT_PEM = File.read("#{Rails.root}/#{PAYPAL_CONFIG[:app_cert_file]}")
  APP_KEY_PEM = File.read("#{Rails.root}/#{PAYPAL_CONFIG[:app_key_file]}")

  ...

  def paypal_data(return_url, notify_url)
    values = {
      :business => PAYPAL_CONFIG[:user],
      :cert_id => PAYPAL_CONFIG[:cert_id],
      :custom => PAYPAL_CONFIG[:secret],
      :cmd => '_cart',
      :upload => 1,
      :return => return_url,
      :notify_url => notify_url,
      :invoice => id,
      :currency_code => 'AUD'
    }
    line_items.each_with_index do |item, i|
      values.merge!({
        "amount_#{i+1}" => "%.2f" % item.unit_price_ex_gst,
        "tax_#{i+1}" => "%.2f" % item.unit_gst,
        "item_name_#{i+1}" => item.product.full_name,
        "item_number_#{i+1}" => item.id,
        "quantity_#{i+1}" => item.quantity
      })
    end
    encrypt_for_paypal(values)
  end

  def encrypt_for_paypal(values)
    signed = OpenSSL::PKCS7::sign(OpenSSL::X509::Certificate.new(APP_CERT_PEM), 
      OpenSSL::PKey::RSA.new(APP_KEY_PEM, ''), 
      values.map { |key, value| "#{key}=#{value}" }.join("\n"), [], OpenSSL::PKCS7::BINARY)
    OpenSSL::PKCS7::encrypt([OpenSSL::X509::Certificate.new(PAYPAL_CERT_PEM)], 
      signed.to_der, 
      OpenSSL::Cipher::Cipher::new("DES3"), 
      OpenSSL::PKCS7::BINARY).to_s.gsub("\n", '')
  end
end

Then I use the following code in the view:

- form_tag PAYPAL_CONFIG[:action_url] do
  %div
    = hidden_field_tag :cmd, '_s-xclick'
    = hidden_field_tag :encrypted, cart.paypal_data(thanks_payments_url, payments_url)
    = image_submit_tag 'paypal-checkout.gif', :alt => 'Check out with PayPal: The safer, easier way to pay'

There don't seem to be any newlines or other characters in the output which I am aware can stuff up the process.

I have checked and double-checked that I am using all the right certificates and certificate ids, and that what has been uploaded to PayPal matches what is in my certs directory.

I have completely run out of ideas to try. Any help or ideas would be greatly appreciated.

Answer 1

Everything is working in staging and production now.

The only thing I can think of is that there was some sort of problem or delay with PayPal and the certificates on their side.