diff --git a/src/pkcs11/pkcs11.h b/src/pkcs11/pkcs11.h
index e24734c6..61bd6dc4 100644
--- a/src/pkcs11/pkcs11.h
+++ b/src/pkcs11/pkcs11.h
@@ -815,6 +815,14 @@ typedef struct CK_RSA_PKCS_PSS_PARAMS {
 
 #define CKZ_DATA_SPECIFIED	(0x00000001UL)
 
+typedef struct CK_GCM_PARAMS {
+	void * pIv;
+	unsigned long ulIvLen;
+	void * pAAD;
+	unsigned long ulAADLen;
+	unsigned long ulTagBits;
+} CK_GCM_PARAMS;
+
 typedef unsigned long ck_rv_t;