--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/encauth/chachapoly/chacha20poly1305_done.c	Fri Feb 09 23:49:22 2018 +0800
@@ -0,0 +1,46 @@
+/* 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
+
+/**
+  Terminate a ChaCha20Poly1305 stream
+  @param st      The ChaCha20Poly1305 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 chacha20poly1305_done(chacha20poly1305_state *st, unsigned char *tag, unsigned long *taglen)
+{
+   unsigned char padzero[16] = { 0 };
+   unsigned long padlen;
+   unsigned char buf[16];
+   int err;
+
+   LTC_ARGCHK(st != NULL);
+
+   padlen = 16 - (unsigned long)(st->ctlen % 16);
+   if (padlen < 16) {
+     if ((err = poly1305_process(&st->poly, padzero, padlen)) != CRYPT_OK) return err;
+   }
+   STORE64L(st->aadlen, buf);
+   STORE64L(st->ctlen, buf + 8);
+   if ((err = poly1305_process(&st->poly, buf, 16)) != CRYPT_OK)           return err;
+   if ((err = poly1305_done(&st->poly, tag, taglen)) != CRYPT_OK)          return err;
+   if ((err = chacha_done(&st->chacha)) != CRYPT_OK)                       return err;
+   return CRYPT_OK;
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */