diff --git a/age/src/encrypted.rs b/age/src/encrypted.rs
index 4570a2bd..06064b2f 100644
--- a/age/src/encrypted.rs
+++ b/age/src/encrypted.rs
@@ -43,7 +43,7 @@ impl<R: io::Read, C: Callbacks> IdentityState<R, C> {
                     filename = filename.unwrap_or_default()
                 )) {
                     Some(passphrase) => passphrase,
-                    None => todo!(),
+                    None => Err(DecryptError::KeyDecryptionFailed)?,
                 };
 
                 let mut identity = scrypt::Identity::new(passphrase);