--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/mac/omac/omac_done.c	Fri May 06 13:23:02 2005 +0000
@@ -0,0 +1,80 @@
+/* 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.org
+ */
+#include "tomcrypt.h"
+
+/** 
+  @file omac_done.c
+  OMAC1 support, terminate a stream, Tom St Denis
+*/
+
+#ifdef OMAC
+
+/**
+  Terminate an OMAC stream
+  @param omac   The OMAC state
+  @param out    [out] Destination for the authentication tag
+  @param outlen [in/out]  The max size and resulting size of the authentication tag
+  @return CRYPT_OK if successful
+*/
+int omac_done(omac_state *omac, unsigned char *out, unsigned long *outlen)
+{
+   int       err, mode;
+   unsigned  x;
+
+   LTC_ARGCHK(omac   != NULL);
+   LTC_ARGCHK(out    != NULL);
+   LTC_ARGCHK(outlen != NULL);
+   if ((err = cipher_is_valid(omac->cipher_idx)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((omac->buflen > (int)sizeof(omac->block)) || (omac->buflen < 0) ||
+       (omac->blklen > (int)sizeof(omac->block)) || (omac->buflen > omac->blklen)) {
+      return CRYPT_INVALID_ARG;
+   }
+
+   /* figure out mode */
+   if (omac->buflen != omac->blklen) {
+      /* add the 0x80 byte */
+      omac->block[omac->buflen++] = 0x80;
+
+      /* pad with 0x00 */
+      while (omac->buflen < omac->blklen) {
+         omac->block[omac->buflen++] = 0x00;
+      }
+      mode = 1;
+   } else {
+      mode = 0;
+   }
+
+   /* now xor prev + Lu[mode] */
+   for (x = 0; x < (unsigned)omac->blklen; x++) {
+       omac->block[x] ^= omac->prev[x] ^ omac->Lu[mode][x];
+   }
+
+   /* encrypt it */
+   cipher_descriptor[omac->cipher_idx].ecb_encrypt(omac->block, omac->block, &omac->key);
+   cipher_descriptor[omac->cipher_idx].done(&omac->key);
+ 
+   /* output it */
+   for (x = 0; x < (unsigned)omac->blklen && x < *outlen; x++) {
+       out[x] = omac->block[x];
+   }
+   *outlen = x;
+
+#ifdef LTC_CLEAN_STACK
+   zeromem(omac, sizeof(*omac));
+#endif
+   return CRYPT_OK;
+}
+
+#endif
+