diff --git a/library/asn1parse.c b/library/asn1parse.c
index 22747d3..83c7c58 100644
--- a/library/asn1parse.c
+++ b/library/asn1parse.c
@@ -461,7 +461,7 @@
     }
 }
 
-mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data *list,
+const mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( const mbedtls_asn1_named_data *list,
                                        const char *oid, size_t len )
 {
     while( list != NULL )