Implemented chacha, based on contribution by Joachim Strömbergson.

ChangeLog

+2014-01-27  Niels Möller  <nisse@lysator.liu.se>
+
+	Chacha implementation, based on contribution by Joachim
+	Strömbergson.
+	* chacha.h: New file.
+	* chacha256-set-key.c (chacha256_set_key): New file and function.
+	* chacha128-set-key.c (chacha128_set_key): New file and function.
+	* chacha-set-key.c (chacha_set_key): New file and function.
+	* chacha-set-iv.c (chacha_set_iv): New file and function.
+	* chacha-core-internal.c (_chacha_core): New file and function.
+	* chacha-crypt.c (chacha_crypt): New file and function.
+	* Makefile.in (nettle_SOURCES): Added chacha files.
+	(HEADERS): Added chacha.h.
+	* testsuite/chacha-test.c: New file.
+	* testsuite/Makefile.in (TS_NETTLE_SOURCES): Added chacha-test.c.
+
 2014-01-26  Niels Möller  <nisse@lysator.liu.se>
 
 	* nettle-internal.h (_NETTLE_AEAD_FIX): Renamed to...

Makefile.in

@@ -86,8 +86,11 @@ nettle_SOURCES = aes-decrypt-internal.c aes-decrypt.c \
 		 camellia256-set-decrypt-key.c \
 		 camellia256-meta.c \
 		 cast128.c cast128-meta.c \
-		 blowfish.c \
-		 cbc.c ctr.c gcm.c \
+		 blowfish.c cbc.c \
+		 chacha-crypt.c chacha-core-internal.c \
+		 chacha-set-iv.c chacha-set-key.c \
+		 chacha128-set-key.c chacha256-set-key.c \
+		 ctr.c gcm.c \
 		 gcm-aes.c gcm-aes128.c gcm-aes192.c gcm-aes256.c \
 		 des.c des3.c des-compat.c eax.c \
 		 hmac.c hmac-md5.c hmac-ripemd160.c hmac-sha1.c \
@@ -159,7 +162,7 @@ hogweed_SOURCES = sexp.c sexp-format.c \
 
 HEADERS = aes.h arcfour.h arctwo.h asn1.h bignum.h blowfish.h \
 	  base16.h base64.h buffer.h camellia.h cast128.h \
-	  cbc.h ctr.h \
+	  cbc.h chacha.h ctr.h \
 	  des.h des-compat.h dsa.h eax.h ecc-curve.h ecc.h ecdsa.h \
 	  gcm.h gosthash94.h hmac.h \
 	  knuth-lfib.h \

chacha-core-internal.c

+/* chacha-core-internal.c
+ *
+ * Core functionality of the ChaCha stream cipher.
+ * Heavily based on the Salsa20 implementation in Nettle.
+ *
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2013 Joachim Strömbergson
+ * Copyright (C) 2012 Simon Josefsson, Niels Möller
+ *  
+ * 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:
+   chacha-ref.c version 2008.01.20.
+   D. J. Bernstein
+   Public domain.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <assert.h>
+#include <string.h>
+
+#include "chacha.h"
+
+#include "macros.h"
+
+#ifndef CHACHA_DEBUG
+# define CHACHA_DEBUG 0
+#endif
+
+#if CHACHA_DEBUG
+# include <stdio.h>
+# define DEBUG(i) do {				\
+    unsigned debug_j;				\
+    for (debug_j = 0; debug_j < 16; debug_j++)	\
+      {						\
+	if (debug_j == 0)			\
+	  fprintf(stderr, "%2d:", (i));		\
+	else if (debug_j % 4 == 0)		\
+	  fprintf(stderr, "\n   ");		\
+	fprintf(stderr, " %8x", x[debug_j]);	\
+      }						\
+    fprintf(stderr, "\n");			\
+  } while (0)
+#else
+# define DEBUG(i)
+#endif
+
+#ifdef WORDS_BIGENDIAN
+#define LE_SWAP32(v)				\
+  ((ROTL32(8,  v) & 0x00FF00FFUL) |		\
+   (ROTL32(24, v) & 0xFF00FF00UL))
+#else
+#define LE_SWAP32(v) (v)
+#endif
+
+#define QROUND(x0, x1, x2, x3) do { \
+  x0 = x0 + x1; x3 = ROTL32(16, (x0 ^ x3)); \
+  x2 = x2 + x3; x1 = ROTL32(12, (x1 ^ x2)); \
+  x0 = x0 + x1; x3 = ROTL32(8,  (x0 ^ x3)); \
+  x2 = x2 + x3; x1 = ROTL32(7,  (x1 ^ x2)); \
+  } while(0)
+
+void
+_chacha_core(uint32_t *dst, const uint32_t *src, unsigned rounds)
+{
+  uint32_t x[_CHACHA_STATE_LENGTH];
+  unsigned i;
+
+  assert ( (rounds & 1) == 0);
+
+  memcpy (x, src, sizeof(x));
+  for (i = 0; i < rounds;i += 2)
+    {
+      DEBUG (i);
+      QROUND(x[0], x[4], x[8],  x[12]);
+      QROUND(x[1], x[5], x[9],  x[13]);
+      QROUND(x[2], x[6], x[10], x[14]);
+      QROUND(x[3], x[7], x[11], x[15]);
+
+      DEBUG (i+1);
+      QROUND(x[0], x[5], x[10], x[15]);
+      QROUND(x[1], x[6], x[11], x[12]);
+      QROUND(x[2], x[7], x[8],  x[13]);
+      QROUND(x[3], x[4], x[9],  x[14]);
+    }
+  DEBUG (i);
+
+  for (i = 0; i < _CHACHA_STATE_LENGTH; i++)
+    {
+      uint32_t t = x[i] + src[i];
+      dst[i] = LE_SWAP32 (t);
+    }
+}
+
+
+
+
+
+
+

chacha-crypt.c

+/* chacha-crypt.c
+ *
+ * The crypt function in the ChaCha stream cipher.
+ * Heavily based on the Salsa20 implementation in Nettle.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2014 Niels Möller
+ * Copyright (C) 2013 Joachim Strömbergson
+ * Copyright (C) 2012 Simon Josefsson
+ *  
+ * 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:
+   chacha-ref.c version 2008.01.20.
+   D. J. Bernstein
+   Public domain.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <string.h>
+
+#include "chacha.h"
+
+#include "macros.h"
+#include "memxor.h"
+
+#define CHACHA_ROUNDS 20
+
+void
+chacha_crypt(struct chacha_ctx *ctx,
+	      size_t length,
+	      uint8_t *c,
+	      const uint8_t *m)
+{
+  if (!length)
+    return;
+  
+  for (;;)
+    {
+      uint32_t x[_CHACHA_STATE_LENGTH];
+
+      _chacha_core (x, ctx->state, CHACHA_ROUNDS);
+
+      ctx->state[9] += (++ctx->state[8] == 0);
+
+      /* stopping at 2^70 length per nonce is user's responsibility */
+      
+      if (length <= CHACHA_BLOCK_SIZE)
+	{
+	  memxor3 (c, m, x, length);
+	  return;
+	}
+      memxor3 (c, m, x, CHACHA_BLOCK_SIZE);
+
+      length -= CHACHA_BLOCK_SIZE;
+      c += CHACHA_BLOCK_SIZE;
+      m += CHACHA_BLOCK_SIZE;
+  }
+}

chacha-set-iv.c

+/* chacha-set-iv.c
+ *
+ * Setting the IV the ChaCha stream cipher.
+ * Based on the Salsa20 implementation in Nettle.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2013 Joachim Strömbergon
+ * Copyright (C) 2012 Simon Josefsson
+ * Copyright (C) 2012, 2014 Niels Möller
+ *  
+ * 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:
+   ChaCha specification (doc id: 4027b5256e17b9796842e6d0f68b0b5e) and reference 
+   implementation dated 2008.01.20
+   D. J. Bernstein
+   Public domain.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <assert.h>
+
+#include "chacha.h"
+
+#include "macros.h"
+
+void
+chacha_set_iv(struct chacha_ctx *ctx, const uint8_t *iv)
+{
+  ctx->state[12] = 0;
+  ctx->state[13] = 0;
+  ctx->state[14] = LE_READ_UINT32(iv + 0);
+  ctx->state[15] = LE_READ_UINT32(iv + 4);
+}

chacha-set-key.c

+/* chacha-set-key.c
+ *
+ * Copyright (C) 2014 Niels Möller
+ *  
+ * 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.
+ */
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdlib.h>
+
+#include "chacha.h"
+
+void
+chacha_set_key(struct chacha_ctx *ctx, size_t length, const uint8_t *key)
+{
+  switch (length)
+    {
+    default:
+      abort ();
+    case CHACHA128_KEY_SIZE:
+      chacha128_set_key (ctx, key);
+      break;
+    case CHACHA256_KEY_SIZE:
+      chacha256_set_key (ctx, key);
+      break;
+    }
+}

chacha.h

+/* chacha.h
+ *
+ * The ChaCha stream cipher.
+ * Heavily based on the Salsa20 source code in Nettle.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2013 Joachim Strömbergson
+ * Copyright (C) 2012 Simon Josefsson
+ * Copyright (C) 2014 Niels Möller
+ *
+ * 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.
+ */
+
+#ifndef NETTLE_CHACHA_H_INCLUDED
+#define NETTLE_CHACHA_H_INCLUDED
+
+#include "nettle-types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Name mangling */
+#define chacha_set_key nettle_chacha_set_key
+#define chacha128_set_key nettle_chacha128_set_key
+#define chacha256_set_key nettle_chacha256_set_key
+#define chacha_set_iv nettle_chacha_set_iv
+#define chacha_crypt nettle_chacha_crypt
+#define _chacha_core _nettle_chacha_core
+
+/* Possible keysizes, and a reasonable default. In octets. */
+#define CHACHA128_KEY_SIZE 16
+#define CHACHA256_KEY_SIZE 32
+#define CHACHA_KEY_SIZE 32
+
+#define CHACHA_BLOCK_SIZE 64
+
+#define CHACHA_IV_SIZE 8
+
+#define _CHACHA_STATE_LENGTH 16
+
+struct chacha_ctx
+{
+  /* Indices 0-3 holds a constant (SIGMA or TAU).
+     Indices 4-11 holds the key.
+     Indices 12-13 holds the block counter.
+     Indices 14-15 holds the IV:
+
+     This creates the state matrix:
+     C C C C
+     K K K K
+     K K K K
+     B B I I
+  */
+  uint32_t state[_CHACHA_STATE_LENGTH];
+};
+
+void
+chacha128_set_key(struct chacha_ctx *ctx, const uint8_t *key);
+
+void
+chacha256_set_key(struct chacha_ctx *ctx, const uint8_t *key);
+
+void
+chacha_set_key(struct chacha_ctx *ctx,
+	       size_t length, const uint8_t *key);
+
+void
+chacha_set_iv(struct chacha_ctx *ctx, const uint8_t *iv);
+
+void
+chacha_crypt(struct chacha_ctx *ctx, size_t length, 
+             uint8_t *dst, const uint8_t *src);
+
+void
+_chacha_core(uint32_t *dst, const uint32_t *src, unsigned rounds);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* NETTLE_CHACHA_H_INCLUDED */

chacha128-set-key.c

+/* chacha128-set-key.c
+ *
+ * ChaCha key setup for 128-bit keys.
+ * Based on the Salsa20 implementation in Nettle.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2013 Joachim Strömbergon
+ * Copyright (C) 2012 Simon Josefsson
+ * Copyright (C) 2012, 2014 Niels Möller
+ *  
+ * 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:
+   ChaCha specification (doc id: 4027b5256e17b9796842e6d0f68b0b5e) and reference 
+   implementation dated 2008.01.20
+   D. J. Bernstein
+   Public domain.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <assert.h>
+#include <string.h>
+
+#include "chacha.h"
+
+#include "macros.h"
+
+void
+chacha128_set_key(struct chacha_ctx *ctx, const uint8_t *key)
+{
+  static const uint32_t tau[4] = {
+    /* "expand 16-byte k" */
+    0x61707865, 0x3120646e, 0x79622d36, 0x6b206574
+  };
+
+  ctx->state[8]  = ctx->state[4] = LE_READ_UINT32(key + 0);
+  ctx->state[9]  = ctx->state[5] = LE_READ_UINT32(key + 4);
+  ctx->state[10] = ctx->state[6] = LE_READ_UINT32(key + 8);
+  ctx->state[11] = ctx->state[7] = LE_READ_UINT32(key + 12);
+
+  memcpy (ctx->state, tau, sizeof(tau));
+}

chacha256-set-key.c

+/* chacha256-set-key.c
+ *
+ * ChaCha key setup for 256-bit keys.
+ * Based on the Salsa20 implementation in Nettle.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2013 Joachim Strömbergon
+ * Copyright (C) 2012 Simon Josefsson
+ * Copyright (C) 2012, 2014 Niels Möller
+ *  
+ * 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:
+   ChaCha specification (doc id: 4027b5256e17b9796842e6d0f68b0b5e) and reference 
+   implementation dated 2008.01.20
+   D. J. Bernstein
+   Public domain.
+*/
+
+#if HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <assert.h>
+#include <string.h>
+
+#include "chacha.h"
+
+#include "macros.h"
+
+void
+chacha256_set_key(struct chacha_ctx *ctx, const uint8_t *key)
+{
+  static const uint32_t sigma[4] = {
+    /* "expand 32-byte k" */
+    0x61707865, 0x3320646e, 0x79622d32, 0x6b206574
+  };
+  ctx->state[4] = LE_READ_UINT32(key + 0);
+  ctx->state[5] = LE_READ_UINT32(key + 4);
+  ctx->state[6] = LE_READ_UINT32(key + 8);
+  ctx->state[7] = LE_READ_UINT32(key + 12);
+
+  ctx->state[8]  = LE_READ_UINT32(key + 16);
+  ctx->state[9]  = LE_READ_UINT32(key + 20);
+  ctx->state[10] = LE_READ_UINT32(key + 24);
+  ctx->state[11] = LE_READ_UINT32(key + 28);
+
+  memcpy (ctx->state, sigma, sizeof(sigma));
+}

testsuite/.test-rules.make

@@ -22,6 +22,9 @@ base64-test$(EXEEXT): base64-test.$(OBJEXT)
 camellia-test$(EXEEXT): camellia-test.$(OBJEXT)
 	$(LINK) camellia-test.$(OBJEXT) $(TEST_OBJS) -o camellia-test$(EXEEXT)
 
+chacha-test$(EXEEXT): chacha-test.$(OBJEXT)
+	$(LINK) chacha-test.$(OBJEXT) $(TEST_OBJS) -o chacha-test$(EXEEXT)
+
 des-test$(EXEEXT): des-test.$(OBJEXT)
 	$(LINK) des-test.$(OBJEXT) $(TEST_OBJS) -o des-test$(EXEEXT)
 

testsuite/Makefile.in

@@ -13,7 +13,7 @@ PRE_LDFLAGS = -L..
 TS_NETTLE_SOURCES = aes-test.c arcfour-test.c arctwo-test.c \
 		    blowfish-test.c cast128-test.c \
 	            base16-test.c base64-test.c \
-		    camellia-test.c \
+		    camellia-test.c chacha-test.c \
 		    des-test.c des3-test.c des-compat-test.c \
 		    md2-test.c md4-test.c md5-test.c md5-compat-test.c \
 		    memxor-test.c gosthash94-test.c \

testsuite/chacha-test.c

+/* chacha-test.c
+ *
+ * Test program for the ChaCha stream cipher implementation.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2013 Joachim Strömbergson
+ * Copyright (C) 2012, 2014 Niels Möller
+ *  
+ * 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.
+ */
+
+#include "testutils.h"
+
+#include "chacha.h"
+
+static void
+test_chacha(const struct tstring *key, const struct tstring *iv,
+	    const struct tstring *expected, unsigned rounds)
+{
+  /* Uses the _chacha_core function to be able to test different
+     numbers of rounds. */
+  /* FIXME: For rounds == 20, use crypt function, support more than
+     one block, and test various short lengths. */
+  uint32_t out[_CHACHA_STATE_LENGTH];
+  
+  struct chacha_ctx ctx;
+
+  ASSERT (expected->length == CHACHA_BLOCK_SIZE);
+
+  chacha_set_key (&ctx, key->length, key->data);
+  ASSERT (iv->length == CHACHA_IV_SIZE);
+  chacha_set_iv(&ctx, iv->data);
+
+  _chacha_core (out, ctx.state, rounds);
+
+  if (!MEMEQ(CHACHA_BLOCK_SIZE, out, expected->data))
+    {
+      printf("Error, expected:\n");
+      tstring_print_hex (expected);
+      printf("Got:\n");