diff --git a/npa/src/npa-tool.c b/npa/src/npa-tool.c
index 3e48c25..e54e833 100644
--- a/npa/src/npa-tool.c
+++ b/npa/src/npa-tool.c
@@ -211,60 +211,52 @@ int npa_translate_apdus(sc_card_t *card, FILE *input)
 }
 
 static int add_to_ASN1_AUXILIARY_DATA(
-        ASN1_AUXILIARY_DATA **templates,
+        ASN1_AUXILIARY_DATA **auxiliary_data,
         int nid, const unsigned char *data, size_t data_len)
 {
     int r;
-    CVC_DISCRETIONARY_DATA_TEMPLATE **template;
+    CVC_DISCRETIONARY_DATA_TEMPLATE *template = NULL;
 
-    if (!templates) {
+    if (!auxiliary_data) {
         r = SC_ERROR_INVALID_ARGUMENTS;
         goto err;
     }
 
-    if (!*templates) {
-        *templates = ASN1_AUXILIARY_DATA_new();
-        if (!*templates) {
+    if (!*auxiliary_data) {
+        *auxiliary_data = ASN1_AUXILIARY_DATA_new();
+        if (!*auxiliary_data) {
             r = SC_ERROR_INTERNAL;
             goto err;
         }
     }
 
-    if (!(*templates)->template1)
-        template = &(*templates)->template1;
-    else if (!(*templates)->template2)
-        template = &(*templates)->template2;
-    else if (!(*templates)->template3)
-        template = &(*templates)->template3;
-    else {
-        fprintf(stderr,
-                "Choose at most three nPA operations.\n");
-        r = SC_ERROR_INVALID_ARGUMENTS;
-        goto err;
-    }
-
-    *template = CVC_DISCRETIONARY_DATA_TEMPLATE_new();
-    if (!*template) {
+    template = CVC_DISCRETIONARY_DATA_TEMPLATE_new();
+    if (!template) {
         r = SC_ERROR_INTERNAL;
         goto err;
     }
 
-    (*template)->type = OBJ_nid2obj(nid);
-    if (!(*template)->type) {
+    template->type = OBJ_nid2obj(nid);
+    if (!template->type) {
         r = SC_ERROR_INTERNAL;
         goto err;
     }
 
     if (data && data_len) {
-        (*template)->discretionary_data3 = ASN1_OCTET_STRING_new();
-        if (!(*template)->discretionary_data3
+        template->discretionary_data3 = ASN1_OCTET_STRING_new();
+        if (!template->discretionary_data3
                 || !M_ASN1_OCTET_STRING_set(
-                    (*template)->discretionary_data3, data, data_len)) {
+                    template->discretionary_data3, data, data_len)) {
             r = SC_ERROR_INTERNAL;
             goto err;
         }
     }
 
+    if (!sk_push((_STACK*) (*auxiliary_data), template)) {
+        r = SC_ERROR_INTERNAL;
+        goto err;
+    }
+
     r = SC_SUCCESS;
 
 err:
diff --git a/npa/src/npa.c b/npa/src/npa.c
index 09e4086..544b719 100644
--- a/npa/src/npa.c
+++ b/npa/src/npa.c
@@ -47,13 +47,14 @@
 
 /* 0x67
  * Auxiliary authenticated data */
-ASN1_ITEM_TEMPLATE(ASN1_AUXILIARY_DATA) =
+ASN1_ITEM_TEMPLATE(ASN1_AUXILIARY_DATA) = 
     ASN1_EX_TEMPLATE_TYPE(
-            ASN1_TFLG_IMPTAG|ASN1_TFLG_APPLICATION,
-            7, ASN1_AUXILIARY_DATA, CVC_DISCRETIONARY_DATA_TEMPLATES)
+            ASN1_TFLG_SEQUENCE_OF|ASN1_TFLG_IMPTAG|ASN1_TFLG_APPLICATION,
+            7, AuxiliaryAuthenticatedData, CVC_DISCRETIONARY_DATA_TEMPLATE)
 ASN1_ITEM_TEMPLATE_END(ASN1_AUXILIARY_DATA)
 IMPLEMENT_ASN1_FUNCTIONS(ASN1_AUXILIARY_DATA)
 
+
 /*
  * MSE:Set AT
  */
@@ -73,7 +74,7 @@ typedef struct npa_mse_cd_st {
  *
  * NPA_MSE_C->auxiliary_data = d2i_ASN1_AUXILIARY_DATA(...)
  *
- * because they both use the same underlieing struct.
+ * because they both use the same underlying struct.
  *
  * See also openssl/crypto/asn1/tasn_dec.c:183
  */
@@ -92,7 +93,7 @@ ASN1_SEQUENCE(NPA_MSE_C) = {
     ASN1_IMP_OPT(NPA_MSE_C, eph_pub_key, ASN1_OCTET_STRING, 0x11),
     /* 0x67
      * Auxiliary authenticated data. See note above. */
-    ASN1_APP_IMP_OPT(NPA_MSE_C, auxiliary_data, CVC_DISCRETIONARY_DATA_TEMPLATES, 7),
+    ASN1_APP_IMP_SEQUENCE_OF_OPT(NPA_MSE_C, auxiliary_data, CVC_DISCRETIONARY_DATA_TEMPLATE, 7),
     /* Certificate Holder Authorization Template */
     ASN1_OPT(NPA_MSE_C, chat, CVC_CHAT),
 } ASN1_SEQUENCE_END(NPA_MSE_C)
diff --git a/npa/src/npa/npa.h b/npa/src/npa/npa.h
index 9902e79..d1a64d3 100644
--- a/npa/src/npa/npa.h
+++ b/npa/src/npa/npa.h
@@ -225,7 +225,7 @@ int npa_reset_retry_counter(sc_card_t *card,
 extern char npa_default_flags;
 
 /** @brief ASN.1 type for authenticated auxiliary data for terminal authentication */
-typedef CVC_DISCRETIONARY_DATA_TEMPLATES ASN1_AUXILIARY_DATA;
+typedef STACK_OF(CVC_DISCRETIONARY_DATA_TEMPLATE) ASN1_AUXILIARY_DATA;
 DECLARE_ASN1_FUNCTIONS(ASN1_AUXILIARY_DATA)
 
 #ifdef  __cplusplus