diff --git a/lib/webauthn/public_key_credential/creation_options.rb b/lib/webauthn/public_key_credential/creation_options.rb
index 74d8f6c5..32e346bf 100644
--- a/lib/webauthn/public_key_credential/creation_options.rb
+++ b/lib/webauthn/public_key_credential/creation_options.rb
@@ -39,6 +39,7 @@ def initialize(
 
         @rp =
           if rp.is_a?(Hash)
+            rp = rp.dup
             rp[:name] ||= relying_party.name
             rp[:id] ||= relying_party.id