--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/encauth/ocb/ocb_done_decrypt.c	Fri May 06 13:23:02 2005 +0000
@@ -0,0 +1,76 @@
+/* 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
+ */
+
+/** 
+   @file ocb_done_decrypt.c
+   OCB implementation, terminate decryption, by Tom St Denis
+*/
+#include "tomcrypt.h"
+
+#ifdef OCB_MODE
+
+/**
+   Terminate a decrypting OCB state
+   @param ocb    The OCB state
+   @param ct     The ciphertext (if any)
+   @param ctlen  The length of the ciphertext (octets)
+   @param pt     [out] The plaintext
+   @param tag    The authentication tag (to compare against)
+   @param taglen The length of the authentication tag provided
+   @param stat    [out] The result of the tag comparison
+   @return CRYPT_OK if the process was successful regardless if the tag is valid
+*/
+int ocb_done_decrypt(ocb_state *ocb, 
+                     const unsigned char *ct,  unsigned long ctlen,
+                           unsigned char *pt, 
+                     const unsigned char *tag, unsigned long taglen, int *stat)
+{
+   int err;
+   unsigned char *tagbuf;
+   unsigned long tagbuflen;
+
+   LTC_ARGCHK(ocb  != NULL);
+   LTC_ARGCHK(pt   != NULL);
+   LTC_ARGCHK(ct   != NULL);
+   LTC_ARGCHK(tag  != NULL);
+   LTC_ARGCHK(stat != NULL);
+
+   /* default to failed */
+   *stat = 0;
+
+   /* allocate memory */
+   tagbuf = XMALLOC(MAXBLOCKSIZE);
+   if (tagbuf == NULL) {
+      return CRYPT_MEM;
+   }
+
+   tagbuflen = MAXBLOCKSIZE;
+   if ((err = s_ocb_done(ocb, ct, ctlen, pt, tagbuf, &tagbuflen, 1)) != CRYPT_OK) {
+      goto LBL_ERR;
+   }
+
+   if (taglen <= tagbuflen && memcmp(tagbuf, tag, taglen) == 0) {
+      *stat = 1;
+   }
+
+   err = CRYPT_OK;
+LBL_ERR:
+#ifdef LTC_CLEAN_STACK
+   zeromem(tagbuf, MAXBLOCKSIZE);
+#endif
+
+   XFREE(tagbuf);
+
+   return err;
+}
+
+#endif
+