--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/encauth/ccm/ccm_add_aad.c	Fri Feb 09 21:44:05 2018 +0800
@@ -0,0 +1,63 @@
+/* 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
+
+/**
+  Add AAD to the CCM state
+  @param ccm       The CCM state
+  @param adata     The additional authentication data to add to the CCM state
+  @param adatalen  The length of the AAD data.
+  @return CRYPT_OK on success
+ */
+int ccm_add_aad(ccm_state *ccm,
+                const unsigned char *adata,  unsigned long adatalen)
+{
+   unsigned long y;
+   int            err;
+
+   LTC_ARGCHK(ccm   != NULL);
+   LTC_ARGCHK(adata != NULL);
+
+   if (ccm->aadlen < ccm->current_aadlen + adatalen) {
+      return CRYPT_INVALID_ARG;
+   }
+   ccm->current_aadlen += adatalen;
+
+   /* now add the data */
+   for (y = 0; y < adatalen; y++) {
+      if (ccm->x == 16) {
+         /* full block so let's encrypt it */
+         if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
+            return err;
+         }
+         ccm->x = 0;
+      }
+      ccm->PAD[ccm->x++] ^= adata[y];
+   }
+
+   /* remainder? */
+   if (ccm->aadlen == ccm->current_aadlen) {
+      if (ccm->x != 0) {
+         if ((err = cipher_descriptor[ccm->cipher].ecb_encrypt(ccm->PAD, ccm->PAD, &ccm->K)) != CRYPT_OK) {
+            return err;
+         }
+      }
+      ccm->x = 0;
+   }
+
+   return CRYPT_OK;
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */