Add a new protocol 2 transport cipher "chacha20-poly1305@openssh.com"

that combines Daniel Bernstein's ChaCha20 stream cipher and Poly1305 MAC
to build an authenticated encryption mode.

Inspired by and similar to Adam Langley's proposal for TLS:
http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-03
but differs in layout used for the MAC calculation and the use of a
second ChaCha20 instance to separately encrypt packet lengths.
Details are in the PROTOCOL.chacha20poly1305 file.

Feedback markus@, naddy@; manpage bits Loganden Velvindron @ AfriNIC
ok markus@ naddy@

1 files changed, 41 insertions, 0 deletions

diff --git a/usr.bin/ssh/cipher-chachapoly.h b/usr.bin/ssh/cipher-chachapoly.h
new file mode 100644
index 00000000000..1628693b200
--- /dev/null
+++ b/usr.bin/ssh/cipher-chachapoly.h
@@ -0,0 +1,41 @@
+/* $OpenBSD: cipher-chachapoly.h,v 1.1 2013/11/21 00:45:44 djm Exp $ */
+
+/*
+ * Copyright (c) Damien Miller 2013 <djm@mindrot.org>
+ *
+ * Permission to use, copy, modify, and 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.
+ */
+#ifndef CHACHA_POLY_AEAD_H
+#define CHACHA_POLY_AEAD_H
+
+#include <sys/types.h>
+#include "chacha.h"
+#include "poly1305.h"
+
+#define CHACHA_KEYLEN	32 /* Only 256 bit keys used here */
+
+struct chachapoly_ctx {
+	struct chacha_ctx main_ctx, header_ctx;
+};
+
+void	chachapoly_init(struct chachapoly_ctx *cpctx,
+    const u_char *key, u_int keylen)
+    __attribute__((__bounded__(__buffer__, 2, 3)));
+int	chachapoly_crypt(struct chachapoly_ctx *cpctx, u_int seqnr,
+    u_char *dest, const u_char *src, u_int len, u_int aadlen, u_int authlen,
+    int do_encrypt);
+int	chachapoly_get_length(struct chachapoly_ctx *cpctx,
+    u_int *plenp, u_int seqnr, const u_char *cp, u_int len)
+    __attribute__((__bounded__(__buffer__, 4, 5)));
+
+#endif /* CHACHA_POLY_AEAD_H */