diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 4470255..36f19b0 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -256,7 +256,8 @@
                        x509_buf *alg );
 int x509_get_alg( unsigned char **p, const unsigned char *end,
                   x509_buf *alg, x509_buf *params );
-int x509_get_rsassa_pss_params( const x509_buf *params, md_type_t *md_alg,
+int x509_get_rsassa_pss_params( const x509_buf *params,
+                                md_type_t *md_alg, md_type_t *mgf_md,
                                 int *salt_len, int *trailer_field );
 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,