diff --git a/src/de.rs b/src/de.rs
index 6c00b3b..50fd21d 100644
--- a/src/de.rs
+++ b/src/de.rs
@@ -42,7 +42,12 @@ struct Deserializer<'a> {
 }
 impl<'a, 'r> serde::de::Deserializer<'a> for &'r mut Deserializer<'a> {
     type Error = SerdeAsn1DerError;
-    
+
+    #[inline]
+    fn is_human_readable(&self) -> bool {
+        false
+    }
+
     fn deserialize_any<V: Visitor<'a>>(self, visitor: V) -> Result<V::Value> {
         match self.object.tag() {
             Boolean::TAG => self.deserialize_bool(visitor),
diff --git a/src/ser.rs b/src/ser.rs
index 1d74ac3..c356551 100644
--- a/src/ser.rs
+++ b/src/ser.rs
@@ -145,7 +145,12 @@ impl<'a, 'r, S: Sink> serde::ser::Serializer for &'r mut Serializer<'a, S> {
     type SerializeMap = KeyValueWriter;
     type SerializeStruct = SequenceWriter<'a, 'r, S>;
     type SerializeStructVariant = KeyValueWriter;
-    
+
+    #[inline]
+    fn is_human_readable(&self) -> bool {
+        false
+    }
+
     fn serialize_bool(self, v: bool) -> Result<Self::Ok> {
         Ok(v.encode(&mut self.sink).propagate(e!("Failed to write boolean"))?)
     }