diff --git a/src/ed25519.rs b/src/ed25519.rs
index 1b6334a..a76b091 100644
--- a/src/ed25519.rs
+++ b/src/ed25519.rs
@@ -93,7 +93,7 @@ pub fn verify_batch(
     public_keys: &[PublicKey],
 ) -> Result<(), SignatureError>
 {
-    const ASSERT_MESSAGE: &'static [u8] = b"The number of messages, signatures, and public keys must be equal.";
+    const ASSERT_MESSAGE: &'static str = "The number of messages, signatures, and public keys must be equal.";
     assert!(signatures.len()  == messages.len(),    ASSERT_MESSAGE);
     assert!(signatures.len()  == public_keys.len(), ASSERT_MESSAGE);
     assert!(public_keys.len() == messages.len(),    ASSERT_MESSAGE);
diff --git a/src/lib.rs b/src/lib.rs
index 1007b6c..fcd52af 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -255,6 +255,8 @@
 #[macro_use]
 extern crate std;
 
+#[cfg(all(feature = "alloc", not(feature = "std")))]
+extern crate alloc;
 extern crate clear_on_drop;
 extern crate curve25519_dalek;
 extern crate failure;