diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index f46a402..dcc6842 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -30,4 +30,5 @@
 			gsm_04_08_gprs.c sgsn_cdr.c sgsn_ares.c
 osmo_sgsn_LDADD = 	\
 			$(top_builddir)/src/libcommon/libcommon.a \
-			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) $(LIBCARES_LIBS) -lrt
+			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) $(LIBCARES_LIBS) \
+			$(LIBCRYPTO_LIBS) -lrt
diff --git a/openbsc/src/gprs/gprs_sgsn.c b/openbsc/src/gprs/gprs_sgsn.c
index f40de0b..9b11c35 100644
--- a/openbsc/src/gprs/gprs_sgsn.c
+++ b/openbsc/src/gprs/gprs_sgsn.c
@@ -41,6 +41,8 @@
 
 #include <time.h>
 
+#include <openssl/rand.h>
+
 #define GPRS_LLME_CHECK_TICK 30
 
 extern struct sgsn_instance *sgsn;
@@ -525,7 +527,9 @@
 	int max_retries = 100;
 
 restart:
-	ptmsi = rand();
+	if (RAND_bytes((uint8_t *) &ptmsi, sizeof(ptmsi)) != 1)
+		goto failed;
+
 	/* Enforce that the 2 MSB are set without loosing the distance between
 	 * identical values. Since rand() has no duplicate values within a
 	 * period (because the size of the state is the same like the size of
diff --git a/openbsc/tests/sgsn/Makefile.am b/openbsc/tests/sgsn/Makefile.am
index 3c202dd..0308b1b 100644
--- a/openbsc/tests/sgsn/Makefile.am
+++ b/openbsc/tests/sgsn/Makefile.am
@@ -34,5 +34,6 @@
 	$(LIBOSMOGSM_LIBS) \
 	$(LIBOSMOGB_LIBS) \
 	$(LIBCARES_LIBS) \
+	$(LIBCRYPTO_LIBS) \
 	-lgtp -lrt