Add missing copyright header.
x25519-x86_64.c, like the rest of crypto/curve25519, is descended from
SUPERCOP. Add the usual copyright header along with the SUPERCOP attribution.
BUG=64
Change-Id: I43f3de0731f33ab2aa48492c4b742e9f23c87fe1
Reviewed-on: https://boringssl-review.googlesource.com/8195
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/curve25519/x25519-x86_64.c b/crypto/curve25519/x25519-x86_64.c
index 9776c75..1bd86a0 100644
--- a/crypto/curve25519/x25519-x86_64.c
+++ b/crypto/curve25519/x25519-x86_64.c
@@ -1,3 +1,24 @@
+/* Copyright (c) 2015, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+/* This code is mostly taken from the ref10 version of Ed25519 in SUPERCOP
+ * 20141124 (http://bench.cr.yp.to/supercop.html). That code is released as
+ * public domain but this file has the ISC license just to keep licencing
+ * simple.
+ *
+ * The field functions are shared by Ed25519 and X25519 where possible. */
+
#include <openssl/curve25519.h>
#include <string.h>
