diff --git a/src/security/sec-tpm-osx.hpp b/src/security/sec-tpm-osx.hpp
index f7d9959..6effb67 100644
--- a/src/security/sec-tpm-osx.hpp
+++ b/src/security/sec-tpm-osx.hpp
@@ -58,7 +58,7 @@
   setInTerminal(bool inTerminal);
 
   virtual bool
-  getInTerminal();
+  getInTerminal() const;
 
   virtual bool
   isLocked();