diff --git a/lib/hx509/cert.c b/lib/hx509/cert.c
index 4571b3bdf..ad866a368 100644
--- a/lib/hx509/cert.c
+++ b/lib/hx509/cert.c
@@ -2248,3 +2248,22 @@ _hx509_cert_get_eku(hx509_context context,
     }
     return 0;
 }
+
+int
+hx509_cert_binary(hx509_context context, hx509_cert c, heim_octet_string *os)
+{
+    size_t size;
+    int ret;
+
+    os->data = NULL;
+    os->length = 0;
+
+    ASN1_MALLOC_ENCODE(Certificate, os->data, os->length, 
+		       _hx509_get_cert(c), &size, ret);
+    if (ret)
+	return ret;
+    if (os->length != size)
+	_hx509_abort("internal ASN.1 encoder error");
+
+    return ret;
+}