diff --git a/src/security/pib/key.cpp b/src/security/pib/key.cpp
index b4e6daf..0d45140 100644
--- a/src/security/pib/key.cpp
+++ b/src/security/pib/key.cpp
@@ -59,13 +59,13 @@
 }
 
 void
-Key::addCertificate(const v2::Certificate& certificate)
+Key::addCertificate(const v2::Certificate& certificate) const
 {
   return lock()->addCertificate(certificate);
 }
 
 void
-Key::removeCertificate(const Name& certName)
+Key::removeCertificate(const Name& certName) const
 {
   return lock()->removeCertificate(certName);
 }
@@ -83,13 +83,13 @@
 }
 
 const v2::Certificate&
-Key::setDefaultCertificate(const Name& certName)
+Key::setDefaultCertificate(const Name& certName) const
 {
   return lock()->setDefaultCertificate(certName);
 }
 
 const v2::Certificate&
-Key::setDefaultCertificate(const v2::Certificate& certificate)
+Key::setDefaultCertificate(const v2::Certificate& certificate) const
 {
   return lock()->setDefaultCertificate(certificate);
 }