diff --git a/ssh/keys.go b/ssh/keys.go
index dadf41a..73697de 100644
--- a/ssh/keys.go
+++ b/ssh/keys.go
@@ -276,7 +276,8 @@ type PublicKey interface {
 	Type() string
 
 	// Marshal returns the serialized key data in SSH wire format,
-	// with the name prefix.
+	// with the name prefix. To unmarshal the returned data, use
+	// the ParsePublicKey function.
 	Marshal() []byte
 
 	// Verify that sig is a signature on the given data using this