--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/encauth/chachapoly/chacha20poly1305_add_aad.c	Fri Feb 09 23:49:22 2018 +0800
@@ -0,0 +1,38 @@
+/* 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_CHACHA20POLY1305_MODE
+
+/**
+  Add AAD to the ChaCha20Poly1305 state
+  @param st     The ChaCha20Poly1305 state
+  @param in     The additional authentication data to add to the ChaCha20Poly1305 state
+  @param inlen  The length of the ChaCha20Poly1305 data.
+  @return CRYPT_OK on success
+ */
+int chacha20poly1305_add_aad(chacha20poly1305_state *st, const unsigned char *in, unsigned long inlen)
+{
+   int err;
+
+   if (inlen == 0) return CRYPT_OK; /* nothing to do */
+   LTC_ARGCHK(st != NULL);
+
+   if (st->aadflg == 0) return CRYPT_ERROR;
+   if ((err = poly1305_process(&st->poly, in, inlen)) != CRYPT_OK) return err;
+   st->aadlen += (ulong64)inlen;
+   return CRYPT_OK;
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */