diff --git a/lib/stellar_base.rb b/lib/stellar_base.rb
index <HASH>..<HASH> 100644
--- a/lib/stellar_base.rb
+++ b/lib/stellar_base.rb
@@ -16,9 +16,11 @@ module StellarBase
   with_configuration do
     has :horizon_url, default: "https://horizon.stellar.org"
     has :modules, default: [:bridge_callbacks]
+
+    has :on_bridge_callback
     has :check_bridge_callbacks_authenticity, default: false
     has :check_bridge_callbacks_mac_payload, default: false
-    has :bridge_callbacks_mac_key
+    has :bridge_callbacks_mac_key, default: false
   end
 
   def self.included_module?(module_name)
diff --git a/spec/support/config.rb b/spec/support/config.rb
index <HASH>..<HASH> 100644
--- a/spec/support/config.rb
+++ b/spec/support/config.rb
@@ -1,8 +1,11 @@
 StellarBase.configure do |c|
   c.modules = %i(bridge_callbacks)
-  c.check_bridge_callbacks_authenticity = false
   c.horizon_url = "https://horizon-testnet.stellar.org"
+
   c.on_bridge_callback = "ProcessBridgeCallback"
+  c.check_bridge_callbacks_authenticity = false
+  c.check_bridge_callbacks_mac_payload = false
+  c.bridge_callbacks_mac_key = "sample"
 end
Add 'check_bridge_callbacks_mac_payload' and 'bridge_callbacks_mac_key' configuration keys