diff --git a/mod_absec.c b/mod_absec.c
index 2e9fc2d..70da0d6 100755
--- a/mod_absec.c
+++ b/mod_absec.c
@@ -303,6 +303,8 @@ static authn_status authn_check_absec(request_rec *r, const char* user, const ch
 
 ////////////////////////////////////////////////////////////////
 // Validate ressource access
+// request_rec contain user/pass if basic auth
+// it could also contain cookies if cookies based auth
 static authz_status authz_check_absec(request_rec *r, const char *require_args, const void *parsed_require_args)
 {
     char *user = r->user;
@@ -362,6 +364,8 @@ static authz_status authz_check_absec(request_rec *r, const char *require_args,
         ap_rprintf(r, "Fichier propriétaire<br/>\r\n");
         ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : Fichier propriétaire<br/>\r\n");
         return AUTHZ_GRANTED;
+    } else {
+        ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : No user access %d", pw->pw_uid);
     }
 
     // If file is group readable and primary group match return content
@@ -369,6 +373,25 @@ static authz_status authz_check_absec(request_rec *r, const char *require_args,
         ap_rprintf(r, "Fichier groupe<br/>\r\n");
         ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : Fichier groupe<br/>\r\n");
         return AUTHZ_GRANTED;
+    } else {
+        ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : No group access %d", pw->pw_gid);
+    }
+
+    // check supplemental groups
+    gid_t grouplist[16];
+    int grouplistsize = 16;
+    int groupreturn;
+    groupreturn = getgrouplist(user, pw->pw_gid, grouplist, &grouplistsize);
+    if (groupreturn >= 0) {
+        ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : liste groups (%d)", grouplistsize);
+        for (int i=0; i<grouplistsize; i++) {
+            ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : group %d", grouplist[i]);
+            // If file is group readable and match a supplemental group return content
+            if ((fperm.st_gid==grouplist[i]) && (fperm.st_mode & 0070 & permmask)) {
+                ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : Fichier group supp");
+                return AUTHZ_GRANTED;
+            }
+        }
     }
 
     ap_log_rerror("mod_absec.c", 282, 1, APLOG_ERR, APR_SUCCESS, r, "authz_check_absec : DENIED<br/>\r\n");