diff --git a/src/luks.rs b/src/luks.rs
index 2c6b9df..f9ab0a9 100644
--- a/src/luks.rs
+++ b/src/luks.rs
@@ -38,6 +38,9 @@ impl LuksDevice {
         &'a mut self,
     ) -> Fido2LuksResult<Box<dyn Iterator<Item = Fido2LuksResult<(u32, Fido2LuksToken)>> + 'a>>
     {
+        if !self.is_luks2()? {
+            return Err(LuksError::Luks2Required.into());
+        }
         Ok(Box::new(
             (0..32)
                 .map(move |i| {