diff --git a/include/osmocom/sgsn/gprs_sgsn.h b/include/osmocom/sgsn/gprs_sgsn.h
index 289e0c4..c176494 100644
--- a/include/osmocom/sgsn/gprs_sgsn.h
+++ b/include/osmocom/sgsn/gprs_sgsn.h
@@ -175,6 +175,7 @@
 	/* Iu: CK, IK, KSI */
 	/* CKSN */
 	enum gprs_ciph_algo	ciph_algo;
+	uint8_t ue_cipher_mask;
 	/* Auth & Ciphering Request reference from 3GPP TS 24.008 § 10.5.5.19: */
 	uint8_t ac_ref_nr_used;