diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 7592348..5a9ed7d 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -276,6 +276,8 @@
                    x509_name *cur );
 int x509_get_alg_null( unsigned char **p, const unsigned char *end,
                        x509_buf *alg );
+int x509_get_alg( unsigned char **p, const unsigned char *end,
+                  x509_buf *alg, x509_buf *params );
 int x509_get_sig( unsigned char **p, const unsigned char *end, x509_buf *sig );
 int x509_get_sig_alg( const x509_buf *sig_oid, md_type_t *md_alg,
                       pk_type_t *pk_alg );