--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/mac/xcbc/xcbc_done.c	Thu Jan 11 02:39:21 2007 +0000
@@ -0,0 +1,77 @@
+/* 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://libtomcrypt.com
+ */
+#include "tomcrypt.h"
+
+/**
+  @file xcbc_done.c
+  XCBC Support, terminate the state
+*/
+
+#ifdef LTC_XCBC
+
+/** Terminate the XCBC-MAC state
+  @param xcbc     XCBC state to terminate
+  @param out      [out] Destination for the MAC tag
+  @param outlen   [in/out] Destination size and final tag size
+  Return CRYPT_OK on success
+*/
+int xcbc_done(xcbc_state *xcbc, unsigned char *out, unsigned long *outlen)
+{
+   int err, x;
+   LTC_ARGCHK(xcbc != NULL);
+   LTC_ARGCHK(out  != NULL);
+
+   /* check structure */
+   if ((err = cipher_is_valid(xcbc->cipher)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((xcbc->blocksize > cipher_descriptor[xcbc->cipher].block_length) || (xcbc->blocksize < 0) ||
+       (xcbc->buflen > xcbc->blocksize) || (xcbc->buflen < 0)) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* which key do we use? */
+   if (xcbc->buflen == xcbc->blocksize) {
+      /* k2 */
+      for (x = 0; x < xcbc->blocksize; x++) {
+         xcbc->IV[x] ^= xcbc->K[1][x];
+      }
+   } else {
+      xcbc->IV[xcbc->buflen] ^= 0x80;
+      /* k3 */
+      for (x = 0; x < xcbc->blocksize; x++) {
+         xcbc->IV[x] ^= xcbc->K[2][x];
+      }
+   }
+
+   /* encrypt */
+   cipher_descriptor[xcbc->cipher].ecb_encrypt(xcbc->IV, xcbc->IV, &xcbc->key);
+   cipher_descriptor[xcbc->cipher].done(&xcbc->key);
+
+   /* extract tag */
+   for (x = 0; x < xcbc->blocksize && (unsigned long)x < *outlen; x++) {
+      out[x] = xcbc->IV[x];
+   }
+   *outlen = x;
+  
+#ifdef LTC_CLEAN_STACK
+   zeromem(xcbc, sizeof(*xcbc));
+#endif
+   return CRYPT_OK;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtomcrypt/src/mac/xcbc/xcbc_done.c,v $ */
+/* $Revision: 1.4 $ */
+/* $Date: 2006/11/07 03:23:46 $ */
+