--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/modes/xts/xts_mult_x.c	Sat Jun 24 17:50:50 2017 +0800
@@ -0,0 +1,42 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://libtom.org
+ */
+#include "tomcrypt.h"
+
+/** 
+  Source donated by Elliptic Semiconductor Inc (www.ellipticsemi.com) to the LibTom Projects
+*/
+
+#ifdef LTC_XTS_MODE
+
+/** multiply by x 
+  @param I      The value to multiply by x (LFSR shift)
+*/
+void xts_mult_x(unsigned char *I)
+{
+  int x;
+  unsigned char t, tt;
+
+  for (x = t = 0; x < 16; x++) {
+     tt   = I[x] >> 7;
+     I[x] = ((I[x] << 1) | t) & 0xFF;
+     t    = tt;
+  }
+  if (tt) {
+     I[0] ^= 0x87;
+  } 
+}
+
+#endif
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */
+