diff --git a/README.markdown b/README.markdown
index 455dfcc..9021028 100644
--- a/README.markdown
+++ b/README.markdown
@@ -16,7 +16,7 @@ It's a Ruby on Rails port of the connexion kits published by the bank.
 ### in an initializer (`config/initializers/paiement_cic.rb`) :
 
 ```ruby
-PaiementCic.configure do |config|
+PaiementCic.default_config.configure do |config|
   # here the hmac key calculated with the js calculator given by CIC
   config.hmac_key = "########################################"
   # Here the TPE number
@@ -32,19 +32,20 @@ PaiementCic.configure do |config|
 end
 ```
 
-You can also specify `hmac_key`, `tpe` and `societe` when initializing `PaiementCic::TPE` and with `paiement_cic_hidden_fields` helper by passing an hash.
+You can also specify different attributes when initializing `PaiementCic::TPE` and with `paiement_cic_hidden_fields` helper by passing an hash.
 ```ruby
 {
   hmac_key: "########################################",
   tpe: "#######",
   societe: "xxxxxxxxxxxxx",
+  env: :test,
 }
 ```
 
 ### in the payment by card view :
 
 ```
-- form_tag PaiementCic.target_url do
+- form_tag PaiementCic.default_config.target_url do
   = paiement_cic_hidden_fields(@order.reference, @order.amount, mail: 'email@example.com', url_retour: edit_order_url(order), url_retour_ok: bank_ok_order_transaction_url(order_transaction), url_retour_err: bank_err_order_transaction_url(order_transaction))
   = submit_tag "Accéder au site de la banque", :style => "font-weight: bold;"
   = image_tag "reassuring_pictograms.jpg", :alt => "Pictogrammes rassurants", :style => "width: 157px;"
diff --git a/lib/paiement_cic.rb b/lib/paiement_cic.rb
index 7fd18d6..921624c 100644
--- a/lib/paiement_cic.rb
+++ b/lib/paiement_cic.rb
@@ -1,3 +1,4 @@
+require 'paiement_cic/config'
 require 'paiement_cic/tpe'
 require 'paiement_cic/railtie' if defined?(Rails)
 
@@ -31,50 +32,23 @@ module PaiementCic
   DEFAULT_BANK = :cm
   DEFAULT_ENV = :test
 
-  class << self
-    attr_accessor :hmac_key, :tpe, :societe
-    attr_writer :target_url
+  def self.default_config
+    @@default_config ||= PaiementCic::Config.new
+  end
 
-    def configure(&block)
-      yield(self) if block_given?
+  def self.hmac_sha1(key, data)
+    length = 64
+
+    if (key.length > length)
+      key = [Digest::SHA1.hexdigest(key)].pack("H*")
     end
 
-    def bank
-      @bank || DEFAULT_BANK
-    end
+    key  = key.ljust(length, 0.chr)
 
-    def bank=(value)
-      raise UnknownBankError unless END_POINTS.keys.include?(value.to_sym)
-      @bank = value
-    end
+    k_ipad = key ^ ''.ljust(length, 54.chr)
+    k_opad = key ^ ''.ljust(length, 92.chr)
 
-    def env
-      @env || DEFAULT_ENV
-    end
-
-    def env=(value)
-      raise UnknownEnvError unless END_POINTS.first.last.include?(value.to_sym)
-      @env = value
-    end
-
-    def target_url
-      @target_url || END_POINTS[self.bank][self.env]
-    end
-
-    def hmac_sha1(key, data)
-      length = 64
-
-      if (key.length > length)
-        key = [Digest::SHA1.hexdigest(key)].pack("H*")
-      end
-
-      key  = key.ljust(length, 0.chr)
-
-      k_ipad = key ^ ''.ljust(length, 54.chr)
-      k_opad = key ^ ''.ljust(length, 92.chr)
-
-      Digest::SHA1.hexdigest(k_opad + [Digest::SHA1.hexdigest(k_ipad + data)].pack("H*"))
-    end
+    Digest::SHA1.hexdigest(k_opad + [Digest::SHA1.hexdigest(k_ipad + data)].pack("H*"))
   end
 
   class UnknownBankError < Exception; end
diff --git a/lib/paiement_cic/config.rb b/lib/paiement_cic/config.rb
new file mode 100644
index 0000000..99d1232
--- /dev/null
+++ b/lib/paiement_cic/config.rb
@@ -0,0 +1,44 @@
+module PaiementCic
+  class Config
+    attr_accessor :hmac_key, :tpe, :societe
+    attr_writer :target_url
+
+    def initialize(attributes = {}, &block)
+      if block_given?
+        configure(&block)
+      else
+        attributes.each do |name, value|
+          setter = "#{name}="
+          next unless respond_to?(setter)
+          send(setter, value)
+        end
+      end
+    end
+
+    def configure(&block)
+      yield self
+    end
+
+    def bank
+      @bank || DEFAULT_BANK
+    end
+
+    def bank=(value)
+      raise UnknownBankError unless END_POINTS.keys.include?(value.to_sym)
+      @bank = value
+    end
+
+    def env
+      @env || DEFAULT_ENV
+    end
+
+    def env=(value)
+      raise UnknownEnvError unless END_POINTS.first.last.include?(value.to_sym)
+      @env = value
+    end
+
+    def target_url
+      @target_url || END_POINTS[self.bank][self.env]
+    end
+  end
+end
diff --git a/lib/paiement_cic/form_helper.rb b/lib/paiement_cic/form_helper.rb
index 7b8efb9..5d2f1a8 100644
--- a/lib/paiement_cic/form_helper.rb
+++ b/lib/paiement_cic/form_helper.rb
@@ -1,9 +1,9 @@
 module PaiementCic::FormHelper
   def paiement_cic_hidden_fields(reference, price, options = {})
     oMac = PaiementCic::TPE.new(options)
-    oa = oMac.config(reference, price, options)
+    oa = oMac.attributes(reference, price, options)
 
-    chaineMAC = oMac.computeHMACSHA1(oa.values.join('*'))
+    chaineMAC = oMac.compute_hmac_sha1(oa.values.join('*'))
 
     url_retour      = options[:url_retour]
     url_retour_ok   = options[:url_retour_ok]
diff --git a/lib/paiement_cic/tpe.rb b/lib/paiement_cic/tpe.rb
index da5af34..0c73729 100644
--- a/lib/paiement_cic/tpe.rb
+++ b/lib/paiement_cic/tpe.rb
@@ -1,23 +1,22 @@
 module PaiementCic
   class TPE
-    attr_accessor :hmac_key, :tpe, :societe
+    attr_accessor :config
 
-    def initialize(options = {})
-      self.hmac_key = options[:hmac_key] || PaiementCic.hmac_key
-      self.tpe = options[:tpe] || PaiementCic.tpe
-      self.societe = options[:societe] || PaiementCic.societe
+    def initialize(options = nil)
+      self.config = options.nil? ? PaiementCic.default_config :
+        PaiementCic::Config.new(options)
     end
 
-    def config(reference, amount_in_cents, options = {})
+    def attributes(reference, amount_in_cents, options = {})
       {
-        'TPE' => tpe,
+        'TPE' => config.tpe,
         'date' => Time.now.strftime(PaiementCic::DATE_FORMAT),
         'montant' => ("%.2f" % amount_in_cents) + "EUR",
         'reference' => reference.to_s,
         'texte-libre' => '',
         'version' => PaiementCic::API_VERSION,
         'lgue' => 'FR',
-        'societe' => societe,
+        'societe' => config.societe,
         'mail' => options[:mail].to_s,
         'nbrech' => options[:nbrech].to_s,
         'dateech1' => options[:dateech1].to_s,
@@ -34,7 +33,7 @@ module PaiementCic
 
     def mac_string params
       [
-        tpe, params["date"], params['montant'], params['reference'], params['texte-libre'],
+        config.tpe, params['date'], params['montant'], params['reference'], params['texte-libre'],
         PaiementCic::API_VERSION, params['code-retour'], params['cvx'], params['vld'], params['brand'],
         params['status3ds'], params['numauto'], params['motifrefus'], params['originecb'],
         params['bincb'], params['hpancb'], params['ipclient'], params['originetr'],
@@ -48,20 +47,21 @@ module PaiementCic
 
     # Check if the HMAC matches the HMAC of the data string
     def valid_hmac?(mac_string, sent_mac)
-      computeHMACSHA1(mac_string) == sent_mac.downcase
+      compute_hmac_sha1(mac_string) == sent_mac.downcase
     end
 
     # Return the HMAC for a data string
-    def computeHMACSHA1(data)
+    def compute_hmac_sha1(data)
       PaiementCic.hmac_sha1(usable_key, data).downcase
     end
+    alias_method :computeHMACSHA1, :compute_hmac_sha1
 
     private
     # Return the key to be used in the hmac function
     def usable_key
 
-      hex_string_key  = hmac_key[0..37]
-      hex_final   = hmac_key[38..40] + "00";
+      hex_string_key  = config.hmac_key[0..37]
+      hex_final   = config.hmac_key[38..40] + "00";
 
       cca0 = hex_final[0].ord