diff --git a/hash.rs b/hash.rs
index 5f85c700..e0b0d83e 100644
--- a/hash.rs
+++ b/hash.rs
@@ -1,8 +1,6 @@
-use std;
-
-import std::ptr;
-import std::str;
-import std::vec;
+import core::ptr;
+import core::str;
+import core::vec;
 
 export hasher;
 export hashtype;
diff --git a/pkey.rs b/pkey.rs
index 08d0fcd7..5c2e2249 100644
--- a/pkey.rs
+++ b/pkey.rs
@@ -1,9 +1,7 @@
-use std;
-
-import std::ptr;
-import std::str;
-import std::unsafe;
-import std::vec;
+import core::ptr;
+import core::str;
+import core::unsafe;
+import core::vec;
 
 export pkeyrole, encrypt, decrypt, sign, verify;
 export pkey, mk_pkey;
diff --git a/symm.rs b/symm.rs
index 8d286897..53d64ebc 100644
--- a/symm.rs
+++ b/symm.rs
@@ -1,8 +1,6 @@
-use std;
-
-import std::ptr;
-import std::str;
-import std::vec;
+import core::ptr;
+import core::str;
+import core::vec;
 
 export crypter;
 export cryptermode;