added chacha_done

src/stream/chacha/chacha_done.c

@@ -0,0 +1,31 @@
+/* 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.
+ */
+
+/* The implementation is based on:
+ * chacha-ref.c version 20080118
+ * Public domain from D. J. Bernstein
+ */
+
+#include "tomcrypt.h"
+
+#ifdef LTC_CHACHA
+
+/**
+  Terminate and clear ChaCha state
+  @param st      The ChaCha state
+  @return CRYPT_OK on success
+*/
+int chacha_done(chacha_state *st)
+{
+   LTC_ARGCHK(st != NULL);
+   XMEMSET(st, 0, sizeof(chacha_state));
+   return CRYPT_OK;
+};
+
+#endif