Hello,
This patch adds a function to use the Salsa20 with 12 rounds.
regards,
Nikos
>From a90fd43ef7e1bbd9e39df7b612aac430169f3f5b Mon Sep 17 00:00:00 2001
From: Nikos Mavrogiannopoulos <[email protected]>
Date: Sun, 17 Mar 2013 14:16:09 +0100
Subject: [PATCH] Added encryption function for 12-round salsa20.
---
Makefile.in | 2 +-
salsa20-crypt.c | 5 ++--
salsa20.h | 7 +++++
salsa20r12-crypt.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 85 insertions(+), 3 deletions(-)
create mode 100644 salsa20r12-crypt.c
diff --git a/Makefile.in b/Makefile.in
index 1ec807b..3e939c7 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -86,7 +86,7 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \
gosthash94.c \
ripemd160.c ripemd160-compress.c ripemd160-meta.c \
salsa20-core-internal.c \
- salsa20-crypt.c salsa20-set-key.c \
+ salsa20-crypt.c salsa20r12-crypt.c salsa20-set-key.c \
sha1.c sha1-compress.c sha1-meta.c \
sha256.c sha256-compress.c sha224-meta.c sha256-meta.c \
sha512.c sha512-compress.c sha384-meta.c sha512-meta.c \
diff --git a/salsa20-crypt.c b/salsa20-crypt.c
index b061b4b..d395d36 100644
--- a/salsa20-crypt.c
+++ b/salsa20-crypt.c
@@ -46,12 +46,13 @@ salsa20_crypt(struct salsa20_ctx *ctx,
uint8_t *c,
const uint8_t *m)
{
+ uint32_t x[_SALSA20_INPUT_LENGTH];
+
if (!length)
return;
for (;;)
{
- uint32_t x[_SALSA20_INPUT_LENGTH];
_salsa20_core (x, ctx->input, 20);
@@ -69,5 +70,5 @@ salsa20_crypt(struct salsa20_ctx *ctx,
length -= SALSA20_BLOCK_SIZE;
c += SALSA20_BLOCK_SIZE;
m += SALSA20_BLOCK_SIZE;
- }
+ }
}
diff --git a/salsa20.h b/salsa20.h
index d95d002..1c5cc4a 100644
--- a/salsa20.h
+++ b/salsa20.h
@@ -39,6 +39,8 @@ extern "C" {
#define salsa20_crypt nettle_salsa20_crypt
#define _salsa20_core _nettle_salsa20_core
+#define salsa20r12_crypt nettle_salsa20r12_crypt
+
/* Minimum and maximum keysizes, and a reasonable default. In
* octets.*/
#define SALSA20_MIN_KEY_SIZE 16
@@ -77,6 +79,11 @@ salsa20_crypt(struct salsa20_ctx *ctx,
const uint8_t *src);
void
+salsa20r12_crypt(struct salsa20_ctx *ctx,
+ unsigned length, uint8_t *dst,
+ const uint8_t *src);
+
+void
_salsa20_core(uint32_t *dst, const uint32_t *src, unsigned rounds);
#ifdef __cplusplus
diff --git a/salsa20r12-crypt.c b/salsa20r12-crypt.c
new file mode 100644
index 0000000..0c82217
--- /dev/null
+++ b/salsa20r12-crypt.c
@@ -0,0 +1,74 @@
+/* salsa20r12-crypt.c
+ *
+ * The Salsa20 stream cipher.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2013 Nikos Mavrogiannopoulos
+ *
+ * The nettle library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ *
+ * The nettle library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the nettle library; see the file COPYING.LIB. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02111-1301, USA.
+ */
+
+/* Based on:
+ salsa20-ref.c version 20051118
+ D. J. Bernstein
+ Public domain.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <string.h>
+
+#include "salsa20.h"
+
+#include "macros.h"
+#include "memxor.h"
+
+void
+salsa20r12_crypt(struct salsa20_ctx *ctx,
+ unsigned length,
+ uint8_t *c,
+ const uint8_t *m)
+{
+ uint32_t x[_SALSA20_INPUT_LENGTH];
+
+ if (!length)
+ return;
+
+ for (;;)
+ {
+
+ _salsa20_core (x, ctx->input, 12);
+
+ ctx->input[9] += (++ctx->input[8] == 0);
+
+ /* stopping at 2^70 length per nonce is user's responsibility */
+
+ if (length <= SALSA20_BLOCK_SIZE)
+ {
+ memxor3 (c, m, (uint8_t *) x, length);
+ return;
+ }
+ memxor3 (c, m, (uint8_t *) x, SALSA20_BLOCK_SIZE);
+
+ length -= SALSA20_BLOCK_SIZE;
+ c += SALSA20_BLOCK_SIZE;
+ m += SALSA20_BLOCK_SIZE;
+ }
+}
--
1.7.10.4
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