diff --git a/library/pkcs5.c b/library/pkcs5.c
index 424952a..061f473 100644
--- a/library/pkcs5.c
+++ b/library/pkcs5.c
@@ -175,6 +175,10 @@
     if( cipher_info == NULL )
         return( POLARSSL_ERR_PKCS5_FEATURE_UNAVAILABLE );
 
+    /*
+     * The value of keylen from pkcs5_parse_pbkdf2_params() is ignored
+     * since it is optional and we don't know if it was set or not
+     */
     keylen = cipher_info->key_length / 8;
 
     if( enc_scheme_params.tag != ASN1_OCTET_STRING ||