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-rw-r--r--libtomcrypt/src/encauth/ocb/ocb_shift_xor.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/libtomcrypt/src/encauth/ocb/ocb_shift_xor.c b/libtomcrypt/src/encauth/ocb/ocb_shift_xor.c
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+++ b/libtomcrypt/src/encauth/ocb/ocb_shift_xor.c
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+/* 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, tomstdenis@gmail.com, http://libtomcrypt.com
+ */
+
+/**
+ @file ocb_shift_xor.c
+ OCB implementation, internal function, by Tom St Denis
+*/
+#include "tomcrypt.h"
+
+#ifdef OCB_MODE
+
+/**
+ Compute the shift/xor for OCB (internal function)
+ @param ocb The OCB state
+ @param Z The destination of the shift
+*/
+void ocb_shift_xor(ocb_state *ocb, unsigned char *Z)
+{
+ int x, y;
+ y = ocb_ntz(ocb->block_index++);
+ for (x = 0; x < ocb->block_len; x++) {
+ ocb->Li[x] ^= ocb->Ls[y][x];
+ Z[x] = ocb->Li[x] ^ ocb->R[x];
+ }
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_shift_xor.c,v $ */
+/* $Revision: 1.4 $ */
+/* $Date: 2006/03/31 14:15:35 $ */