diff --git a/src/libmsc/token_auth.c b/src/libmsc/token_auth.c
new file mode 100644
index 0000000..3404dd4
--- /dev/null
+++ b/src/libmsc/token_auth.c
@@ -0,0 +1,153 @@
+/* SMS based token authentication for ad-hoc GSM networks */
+
+/* (C) 2009 by Harald Welte <laforge@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdio.h>
+#include <osmocore/talloc.h>
+#include <openbsc/signal.h>
+#include <openbsc/gsm_data.h>
+#include <openbsc/gsm_04_11.h>
+#include <openbsc/gsm_04_08.h>
+#include <openbsc/gsm_subscriber.h>
+#include <openbsc/chan_alloc.h>
+#include <openbsc/db.h>
+
+#define TOKEN_SMS_TEXT "HAR 2009 GSM.  Register at http://har2009.gnumonks.org/ " \
+			"Your IMSI is %s, auth token is %08X, phone no is %s."
+
+static char *build_sms_string(struct gsm_subscriber *subscr, u_int32_t token)
+{
+	char *sms_str;
+	unsigned int len;
+
+	len = strlen(subscr->imsi) + 8 + strlen(TOKEN_SMS_TEXT);
+	sms_str = talloc_size(tall_bsc_ctx, len);
+	if (!sms_str)
+		return NULL;
+
+	snprintf(sms_str, len, TOKEN_SMS_TEXT, subscr->imsi, token,
+		 subscr->extension);
+	sms_str[len-1] = '\0';
+
+	return sms_str;
+}
+
+static int token_subscr_cb(unsigned int subsys, unsigned int signal,
+			void *handler_data, void *signal_data)
+{
+	struct gsm_subscriber *subscr = signal_data;
+	struct gsm_sms *sms;
+	int rc = 0;
+
+	if (signal != S_SUBSCR_ATTACHED)
+		return 0;
+
+	if (subscr->net->auth_policy != GSM_AUTH_POLICY_TOKEN)
+		return 0;
+
+	if (subscr->flags & GSM_SUBSCRIBER_FIRST_CONTACT) {
+		u_int32_t token;
+		char *sms_str;
+
+		/* we've seen this subscriber for the first time. */
+		rc = db_subscriber_alloc_token(subscr, &token);
+		if (rc != 0) {
+			rc = -EIO;
+			goto unauth;
+		}
+
+		sms_str = build_sms_string(subscr, token);
+		if (!sms_str) {
+			rc = -ENOMEM;
+			goto unauth;
+		}
+
+		sms = sms_from_text(subscr, 0, sms_str);
+		talloc_free(sms_str);
+		if (!sms) {
+			rc = -ENOMEM;
+			goto unauth;
+		}
+
+		rc = gsm411_send_sms_subscr(subscr, sms);
+
+		/* FIXME: else, delete the subscirber from database */
+unauth:
+
+		/* make sure we don't allow him in again unless he clicks the web UI */
+		subscr->authorized = 0;
+		db_sync_subscriber(subscr);
+		if (rc) {
+			struct gsm_subscriber_connection *conn = connection_for_subscr(subscr);
+			if (conn) {
+				u_int8_t auth_rand[16];
+				/* kick the subscriber off the network */
+				gsm48_tx_mm_auth_req(conn, auth_rand, 0);
+				gsm48_tx_mm_auth_rej(conn);
+				/* FIXME: close the channel early ?*/
+				//gsm48_send_rr_Release(lchan);
+			}
+		}
+	}
+
+	return rc;
+}
+
+static int token_sms_cb(unsigned int subsys, unsigned int signal,
+			void *handler_data, void *signal_data)
+{
+	struct sms_signal_data *sig = signal_data;
+	struct gsm_sms *sms = sig->sms;;
+	struct gsm_subscriber_connection *conn;
+	u_int8_t auth_rand[16];
+
+
+	if (signal != S_SMS_DELIVERED)
+		return 0;
+
+
+	/* these are not the droids we've been looking for */
+	if (!sms->receiver ||
+	    !(sms->receiver->flags & GSM_SUBSCRIBER_FIRST_CONTACT))
+		return 0;
+
+
+	if (sms->receiver->net->auth_policy != GSM_AUTH_POLICY_TOKEN)
+		return 0;
+
+
+	conn = connection_for_subscr(sms->receiver);
+	if (conn) {
+		/* kick the subscriber off the network */
+		gsm48_tx_mm_auth_req(conn, auth_rand, 0);
+		gsm48_tx_mm_auth_rej(conn);
+		/* FIXME: close the channel early ?*/
+		//gsm48_send_rr_Release(lchan);
+	}
+
+	return 0;
+}
+
+//static __attribute__((constructor)) void on_dso_load_token(void)
+void on_dso_load_token(void)
+{
+	register_signal_handler(SS_SUBSCR, token_subscr_cb, NULL);
+	register_signal_handler(SS_SMS, token_sms_cb, NULL);
+}