[u/mdw/catacomb] / skipjack.c

/* -*-c-*-
 *
 * $Id: skipjack.c,v 1.4 2004/04/02 01:03:49 mdw Exp $
 *
 * The Skipjack block cipher
 *
 * (c) 2000 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * Catacomb 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 Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: skipjack.c,v $
 * Revision 1.4  2004/04/02 01:03:49  mdw
 * Miscellaneous constification.
 *
 * Revision 1.3  2000/08/01 00:28:34  mdw
 * Performance improvement: read keys in as 32-bit words and deal them out
 * byte-by-byte.
 *
 * Revision 1.2  2000/07/15 20:48:45  mdw
 * Remove some useless tests in the G function.
 *
 * Revision 1.1  2000/07/15 15:39:33  mdw
 * The NSA's Skipjack block cipher.
 *
 */

/*----- Header files ------------------------------------------------------*/

#include <mLib/bits.h>

#include "blkc.h"
#include "gcipher.h"
#include "skipjack.h"
#include "skipjack-tab.h"

/*----- Global variables --------------------------------------------------*/

const octet skipjack_keysz[] = { KSZ_SET, 10, 0 };

/*----- The Skipjack S-box ------------------------------------------------*/

static const octet f[256] = SKIPJACK_S;

/*----- Main code ---------------------------------------------------------*/

/* --- @skipjack_init@ --- *
 *
 * Arguments:   @skipjack_ctx *k@ = pointer to key block
 *              @const void *buf@ = pointer to key buffer
 *              @size_t sz@ = size of key material
 *
 * Returns:     ---
 *
 * Use:         Initializes a Skipjack key buffer.  The key buffer must be
 *		exactly 10 bytes long.
 */

void skipjack_init(skipjack_ctx *k, const void *buf, size_t sz)
{
  const octet *b = buf;
  uint32 crud;
  KSZ_ASSERT(skipjack, sz);
  k->ka = LOAD32(b);
  k->kb = LOAD32(b + 4);
  crud = LOAD16(b + 8);
  k->kc = U32((crud << 16) | (k->ka >> 16));
  k->kd = U32((k->ka << 16) | (k->kb >> 16));
  k->ke = U32((k->kb << 16) | crud);
  crud = 0;
}

/* --- @skipjack_eblk@, @skipjack_dblk@ --- *
 *
 * Arguments:   @const skipjack_ctx *k@ = pointer to key block
 *              @const uint32 s[2]@ = pointer to source block
 *              @uint32 d[2]@ = pointer to skipjacktination block
 *
 * Returns:     ---
 *
 * Use:         Low-level block encryption and decryption.
 */

#define G(x, k) do {							\
  octet _x = U8(x >> 8), _y = U8(x);					\
  _x ^= f[_y ^ U8(k >> 24)];						\
  _y ^= f[_x ^ U8(k >> 16)];						\
  _x ^= f[_y ^ U8(k >>  8)];						\
  _y ^= f[_x ^ U8(k >>  0)];						\
  x = (_x << 8) | _y;							\
} while (0)

#define RULE_A(w, x, y, z, n, k) do {					\
  G(w, k); z ^= w ^ n++;						\
} while (0)

#define RULE_B(w, x, y, z, n, k) do {					\
  x ^= w ^ n++; G(w, k);						\
} while (0)

void skipjack_eblk(const skipjack_ctx *k, const uint32 *s, uint32 *d)
{
  unsigned n = 1;
  uint16 w = U16(s[0] >> 16), x = U16(s[0]);
  uint16 y = U16(s[1] >> 16), z = U16(s[1]);
  uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;

  RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
  RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
  RULE_A(w, x, y, z, n, ke); RULE_A(z, w, x, y, n, ka);
  RULE_A(y, z, w, x, n, kb); RULE_A(x, y, z, w, n, kc);
  RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
  RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);
  RULE_B(w, x, y, z, n, kc); RULE_B(z, w, x, y, n, kd);
  RULE_B(y, z, w, x, n, ke); RULE_B(x, y, z, w, n, ka);
  RULE_A(w, x, y, z, n, kb); RULE_A(z, w, x, y, n, kc);
  RULE_A(y, z, w, x, n, kd); RULE_A(x, y, z, w, n, ke);
  RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
  RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
  RULE_B(w, x, y, z, n, ke); RULE_B(z, w, x, y, n, ka);
  RULE_B(y, z, w, x, n, kb); RULE_B(x, y, z, w, n, kc);
  RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
  RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);

  d[0] = ((uint32)w << 16) | (uint32)x;
  d[1] = ((uint32)y << 16) | (uint32)z;
}

#define G_INV(x, k) do {						\
  octet _x = U8(x >> 8), _y = U8(x);					\
  _y ^= f[_x ^ U8(k >>  0)];						\
  _x ^= f[_y ^ U8(k >>  8)];						\
  _y ^= f[_x ^ U8(k >> 16)];						\
  _x ^= f[_y ^ U8(k >> 24)];						\
  x = (_x << 8) | _y;							\
} while (0)

#define RULE_A_INV(w, x, y, z, n, i) do {				\
  w ^= x ^ --n; G_INV(x, i);						\
} while (0)

#define RULE_B_INV(w, x, y, z, n, i) do {				\
  G_INV(x, i); y ^= x ^ --n;						\
} while (0)

void skipjack_dblk(const skipjack_ctx *k, const uint32 *s, uint32 *d)
{
  unsigned n = 33;
  uint16 w = U16(s[0] >> 16), x = U16(s[0]);
  uint16 y = U16(s[1] >> 16), z = U16(s[1]);
  uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;

  RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
  RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
  RULE_B_INV(w, x, y, z, n, kc); RULE_B_INV(x, y, z, w, n, kb);
  RULE_B_INV(y, z, w, x, n, ka); RULE_B_INV(z, w, x, y, n, ke);
  RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
  RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);
  RULE_A_INV(w, x, y, z, n, ke); RULE_A_INV(x, y, z, w, n, kd);
  RULE_A_INV(y, z, w, x, n, kc); RULE_A_INV(z, w, x, y, n, kb);
  RULE_B_INV(w, x, y, z, n, ka); RULE_B_INV(x, y, z, w, n, ke);
  RULE_B_INV(y, z, w, x, n, kd); RULE_B_INV(z, w, x, y, n, kc);
  RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
  RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
  RULE_A_INV(w, x, y, z, n, kc); RULE_A_INV(x, y, z, w, n, kb);
  RULE_A_INV(y, z, w, x, n, ka); RULE_A_INV(z, w, x, y, n, ke);
  RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
  RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);

  d[0] = ((uint32)w << 16) | (uint32)x;
  d[1] = ((uint32)y << 16) | (uint32)z;
}

BLKC_TEST(SKIPJACK, skipjack)

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
6a0a5bdc	1	/* --c--
6a0a5bdc	2	*
4e66da02	3	* $Id: skipjack.c,v 1.4 2004/04/02 01:03:49 mdw Exp $
6a0a5bdc	4	*
	5	* The Skipjack block cipher
	6	*
	7	* (c) 2000 Straylight/Edgeware
	8	*/
	9
	10	/----- Licensing notice --------------------------------------------------
	11	*
	12	* This file is part of Catacomb.
	13	*
	14	* Catacomb is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU Library General Public License as
	16	* published by the Free Software Foundation; either version 2 of the
	17	* License, or (at your option) any later version.
	18	*
	19	* Catacomb is distributed in the hope that it will be useful,
	20	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	21	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	22	* GNU Library General Public License for more details.
	23	*
	24	* You should have received a copy of the GNU Library General Public
	25	* License along with Catacomb; if not, write to the Free
	26	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	27	* MA 02111-1307, USA.
	28	*/
	29
	30	/----- Revision history --------------------------------------------------
	31	*
	32	* $Log: skipjack.c,v $
4e66da02	33	* Revision 1.4 2004/04/02 01:03:49 mdw
	34	* Miscellaneous constification.
	35	*
fe371977	36	* Revision 1.3 2000/08/01 00:28:34 mdw
	37	* Performance improvement: read keys in as 32-bit words and deal them out
	38	* byte-by-byte.
	39	*
5125b5b7	40	* Revision 1.2 2000/07/15 20:48:45 mdw
	41	* Remove some useless tests in the G function.
	42	*
6a0a5bdc	43	* Revision 1.1 2000/07/15 15:39:33 mdw
	44	* The NSA's Skipjack block cipher.
	45	*
	46	*/
	47
	48	/----- Header files ------------------------------------------------------/
	49
	50	#include <mLib/bits.h>
	51
	52	#include "blkc.h"
	53	#include "gcipher.h"
	54	#include "skipjack.h"
	55	#include "skipjack-tab.h"
	56
	57	/----- Global variables --------------------------------------------------/
	58
	59	const octet skipjack_keysz[] = { KSZ_SET, 10, 0 };
	60
	61	/----- The Skipjack S-box ------------------------------------------------/
	62
4e66da02	63	static const octet f[256] = SKIPJACK_S;
6a0a5bdc	64
	65	/----- Main code ---------------------------------------------------------/
	66
	67	/* --- @skipjack_init@ --- *
	68	*
	69	* Arguments: @skipjack_ctx *k@ = pointer to key block
	70	* @const void *buf@ = pointer to key buffer
	71	* @size_t sz@ = size of key material
	72	*
	73	* Returns: ---
	74	*
	75	* Use: Initializes a Skipjack key buffer. The key buffer must be
	76	* exactly 10 bytes long.
	77	*/
	78
	79	void skipjack_init(skipjack_ctx k, const void buf, size_t sz)
	80	{
fe371977	81	const octet *b = buf;
fe371977	82	uint32 crud;
6a0a5bdc	83	KSZ_ASSERT(skipjack, sz);
fe371977	84	k->ka = LOAD32(b);
	85	k->kb = LOAD32(b + 4);
	86	crud = LOAD16(b + 8);
	87	k->kc = U32((crud << 16) \| (k->ka >> 16));
	88	k->kd = U32((k->ka << 16) \| (k->kb >> 16));
	89	k->ke = U32((k->kb << 16) \| crud);
	90	crud = 0;
6a0a5bdc	91	}
	92
	93	/* --- @skipjack_eblk@, @skipjack_dblk@ --- *
	94	*
	95	* Arguments: @const skipjack_ctx *k@ = pointer to key block
	96	* @const uint32 s[2]@ = pointer to source block
	97	* @uint32 d[2]@ = pointer to skipjacktination block
	98	*
	99	* Returns: ---
	100	*
	101	* Use: Low-level block encryption and decryption.
	102	*/
	103
fe371977	104	#define G(x, k) do { \
6a0a5bdc	105	octet _x = U8(x >> 8), _y = U8(x); \
fe371977	106	_x ^= f[_y ^ U8(k >> 24)]; \
	107	_y ^= f[_x ^ U8(k >> 16)]; \
	108	_x ^= f[_y ^ U8(k >> 8)]; \
	109	_y ^= f[_x ^ U8(k >> 0)]; \
	110	x = (_x << 8) \| _y; \
6a0a5bdc	111	} while (0)
6a0a5bdc	112
fe371977	113	#define RULE_A(w, x, y, z, n, k) do { \
fe371977	114	G(w, k); z ^= w ^ n++; \
6a0a5bdc	115	} while (0)
6a0a5bdc	116
fe371977	117	#define RULE_B(w, x, y, z, n, k) do { \
fe371977	118	x ^= w ^ n++; G(w, k); \
6a0a5bdc	119	} while (0)
	120
	121	void skipjack_eblk(const skipjack_ctx k, const uint32 s, uint32 *d)
	122	{
6a0a5bdc	123	unsigned n = 1;
	124	uint16 w = U16(s[0] >> 16), x = U16(s[0]);
	125	uint16 y = U16(s[1] >> 16), z = U16(s[1]);
fe371977	126	uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;
	127
	128	RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
	129	RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
	130	RULE_A(w, x, y, z, n, ke); RULE_A(z, w, x, y, n, ka);
	131	RULE_A(y, z, w, x, n, kb); RULE_A(x, y, z, w, n, kc);
	132	RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
	133	RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);
	134	RULE_B(w, x, y, z, n, kc); RULE_B(z, w, x, y, n, kd);
	135	RULE_B(y, z, w, x, n, ke); RULE_B(x, y, z, w, n, ka);
	136	RULE_A(w, x, y, z, n, kb); RULE_A(z, w, x, y, n, kc);
	137	RULE_A(y, z, w, x, n, kd); RULE_A(x, y, z, w, n, ke);
	138	RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
	139	RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
	140	RULE_B(w, x, y, z, n, ke); RULE_B(z, w, x, y, n, ka);
	141	RULE_B(y, z, w, x, n, kb); RULE_B(x, y, z, w, n, kc);
	142	RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
	143	RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);
6a0a5bdc	144
	145	d[0] = ((uint32)w << 16) \| (uint32)x;
	146	d[1] = ((uint32)y << 16) \| (uint32)z;
	147	}
	148
fe371977	149	#define G_INV(x, k) do { \
6a0a5bdc	150	octet _x = U8(x >> 8), _y = U8(x); \
fe371977	151	_y ^= f[_x ^ U8(k >> 0)]; \
	152	_x ^= f[_y ^ U8(k >> 8)]; \
	153	_y ^= f[_x ^ U8(k >> 16)]; \
	154	_x ^= f[_y ^ U8(k >> 24)]; \
	155	x = (_x << 8) \| _y; \
6a0a5bdc	156	} while (0)
	157
	158	#define RULE_A_INV(w, x, y, z, n, i) do { \
	159	w ^= x ^ --n; G_INV(x, i); \
	160	} while (0)
	161
	162	#define RULE_B_INV(w, x, y, z, n, i) do { \
	163	G_INV(x, i); y ^= x ^ --n; \
	164	} while (0)
	165
	166	void skipjack_dblk(const skipjack_ctx k, const uint32 s, uint32 *d)
	167	{
6a0a5bdc	168	unsigned n = 33;
	169	uint16 w = U16(s[0] >> 16), x = U16(s[0]);
	170	uint16 y = U16(s[1] >> 16), z = U16(s[1]);
fe371977	171	uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;
	172
	173	RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
	174	RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
	175	RULE_B_INV(w, x, y, z, n, kc); RULE_B_INV(x, y, z, w, n, kb);
	176	RULE_B_INV(y, z, w, x, n, ka); RULE_B_INV(z, w, x, y, n, ke);
	177	RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
	178	RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);
	179	RULE_A_INV(w, x, y, z, n, ke); RULE_A_INV(x, y, z, w, n, kd);
	180	RULE_A_INV(y, z, w, x, n, kc); RULE_A_INV(z, w, x, y, n, kb);
	181	RULE_B_INV(w, x, y, z, n, ka); RULE_B_INV(x, y, z, w, n, ke);
	182	RULE_B_INV(y, z, w, x, n, kd); RULE_B_INV(z, w, x, y, n, kc);
	183	RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
	184	RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
	185	RULE_A_INV(w, x, y, z, n, kc); RULE_A_INV(x, y, z, w, n, kb);
	186	RULE_A_INV(y, z, w, x, n, ka); RULE_A_INV(z, w, x, y, n, ke);
	187	RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
	188	RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);
6a0a5bdc	189
	190	d[0] = ((uint32)w << 16) \| (uint32)x;
	191	d[1] = ((uint32)y << 16) \| (uint32)z;
	192	}
	193
	194	BLKC_TEST(SKIPJACK, skipjack)
	195
	196	/----- That's all, folks -------------------------------------------------/