--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/stream/chacha/chacha_keystream.c	Fri Feb 09 21:44:05 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.
+ */
+
+/* The implementation is based on:
+ * chacha-ref.c version 20080118
+ * Public domain from D. J. Bernstein
+ */
+
+#include "tomcrypt.h"
+
+#ifdef LTC_CHACHA
+
+/**
+  Generate a stream of random bytes via ChaCha
+  @param st      The ChaCha20 state
+  @param out     [out] The output buffer
+  @param outlen  The output length
+  @return CRYPT_OK on success
+ */
+int chacha_keystream(chacha_state *st, unsigned char *out, unsigned long outlen)
+{
+   if (outlen == 0) return CRYPT_OK; /* nothing to do */
+   LTC_ARGCHK(out != NULL);
+   XMEMSET(out, 0, outlen);
+   return chacha_crypt(st, out, outlen, out);
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */