diff --git a/lib/devise/strategies/saml.rb b/lib/devise/strategies/saml.rb
index 2600bc4..dfb858e 100644
--- a/lib/devise/strategies/saml.rb
+++ b/lib/devise/strategies/saml.rb
@@ -1,53 +1,53 @@
 require 'securerandom'
 require 'devise/strategies/authenticatable'
 
 module Devise
   module Strategies
     class SamlAuthenticatable < Authenticatable
       def valid?
         return false unless persistent_id.present?
         return false unless mail.present?
 
         return true if WebDNS.settings[:saml_required_entitlement].nil?
 
         entitlement.present? &&
           entitlement.include?(WebDNS.settings[:saml_required_entitlement])
       end
 
       def authenticate!
         if !WebDNS.settings[:saml]
           return fail!('SAML is disabled')
         end
 
-        identifier = ['saml', persistent_id].join(':')
+        identifier = ['saml', remote_user].join(':')
         user = mapping.to.find_or_initialize_by(identifier: identifier)
 
         return fail!('Wrong credentials') unless user
 
         # Update user attributes
         user.email = mail
         user.password = SecureRandom.hex(15) if user.new_record?
         user.save!
 
         success!(user)
       end
 
       private
 
-      def persistent_id
-        request.headers['PERSISTENT-ID']
+      def remote_user
+        request.headers['REMOTE-USER']
       end
 
       def mail
         request.headers['MAIL']
       end
 
       def entitlement
         request.headers['ENTITLEMENT']
       end
 
     end
   end
 end
 
 Warden::Strategies.add(:saml, Devise::Strategies::SamlAuthenticatable)