diff --git a/openpgp-card/src/card_app.rs b/openpgp-card/src/card_app.rs
index 0b023b8..2c5426d 100644
--- a/openpgp-card/src/card_app.rs
+++ b/openpgp-card/src/card_app.rs
@@ -522,7 +522,7 @@ impl CardApp {
         let mut algo_attributes = vec![0x01];
 
         // Length of modulus n in bit
-        algo_attributes.extend(algo_attrs.len_n.to_be_bytes());
+        algo_attributes.extend(&algo_attrs.len_n.to_be_bytes());
 
         // Length of public exponent e in bit
         algo_attributes.push(0x00);