diff --git a/cryptoki/src/mechanism/mod.rs b/cryptoki/src/mechanism/mod.rs
index 0b501169..c18f2b56 100644
--- a/cryptoki/src/mechanism/mod.rs
+++ b/cryptoki/src/mechanism/mod.rs
@@ -14,6 +14,7 @@ use log::error;
 use std::convert::{TryFrom, TryInto};
 use std::ffi::c_void;
 use std::fmt::Formatter;
+use std::mem::size_of;
 use std::ops::Deref;
 use std::ptr::null_mut;
 
diff --git a/cryptoki/src/object.rs b/cryptoki/src/object.rs
index baa1e4d2..d66d97c4 100644
--- a/cryptoki/src/object.rs
+++ b/cryptoki/src/object.rs
@@ -11,6 +11,7 @@ use std::convert::TryFrom;
 use std::convert::TryInto;
 use std::ffi::c_void;
 use std::fmt::Formatter;
+use std::mem::size_of;
 use std::ops::Deref;
 
 #[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]