--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/encauth/ccm/ccm_done.c	Fri Feb 09 21:44:05 2018 +0800
@@ -0,0 +1,65 @@
+/* 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.
+ */
+#include "tomcrypt.h"
+
+#ifdef LTC_CCM_MODE
+
+/**
+  Terminate a CCM stream
+  @param ccm     The CCM state
+  @param tag     [out] The destination for the MAC tag
+  @param taglen  [in/out]  The length of the MAC tag
+  @return CRYPT_OK on success
+ */
+int ccm_done(ccm_state *ccm,
+             unsigned char *tag,    unsigned long *taglen)
+{
+   unsigned long x, y;
+   int            err;
+
+   LTC_ARGCHK(ccm != NULL);
+
+   /* Check all data have been processed */
+   if (ccm->ptlen != ccm->current_ptlen) {
+      return CRYPT_ERROR;
+   }
+
+   LTC_ARGCHK(tag    != NULL);
+   LTC_ARGCHK(taglen != NULL);
+
+   if (ccm->x != 0) {
+      if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
+         return err;
+      }
+   }
+
+   /* setup CTR for the TAG (zero the count) */
+   for (y = 15; y > 15 - ccm->L; y--) {
+      ccm->ctr[y] = 0x00;
+   }
+   if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->ctr, ccm->CTRPAD, &ccm->K)) != CRYPT_OK) {
+      return err;
+   }
+
+   cipher_descriptor[ccm->cipher].done(&ccm->K);
+
+   /* store the TAG */
+   for (x = 0; x < 16 && x < *taglen; x++) {
+      tag[x] = ccm->PAD[x] ^ ccm->CTRPAD[x];
+   }
+   *taglen = x;
+
+   return CRYPT_OK;
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */