[u/mdw/catacomb] / skipjack.c

/* -*-c-*-
 *
 * $Id: skipjack.c,v 1.3 2000/08/01 00:28:34 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 1.3  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 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	*
fe371977	3	* $Id: skipjack.c,v 1.3 2000/08/01 00:28:34 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 $
fe371977	33	* Revision 1.3 2000/08/01 00:28:34 mdw
	34	* Performance improvement: read keys in as 32-bit words and deal them out
	35	* byte-by-byte.
	36	*
5125b5b7	37	* Revision 1.2 2000/07/15 20:48:45 mdw
	38	* Remove some useless tests in the G function.
	39	*
6a0a5bdc	40	* Revision 1.1 2000/07/15 15:39:33 mdw
	41	* The NSA's Skipjack block cipher.
	42	*
	43	*/
	44
	45	/----- Header files ------------------------------------------------------/
	46
	47	#include <mLib/bits.h>
	48
	49	#include "blkc.h"
	50	#include "gcipher.h"
	51	#include "skipjack.h"
	52	#include "skipjack-tab.h"
	53
	54	/----- Global variables --------------------------------------------------/
	55
	56	const octet skipjack_keysz[] = { KSZ_SET, 10, 0 };
	57
	58	/----- The Skipjack S-box ------------------------------------------------/
	59
	60	static octet f[256] = SKIPJACK_S;
	61
	62	/----- Main code ---------------------------------------------------------/
	63
	64	/* --- @skipjack_init@ --- *
	65	*
	66	* Arguments: @skipjack_ctx *k@ = pointer to key block
	67	* @const void *buf@ = pointer to key buffer
	68	* @size_t sz@ = size of key material
	69	*
	70	* Returns: ---
	71	*
	72	* Use: Initializes a Skipjack key buffer. The key buffer must be
	73	* exactly 10 bytes long.
	74	*/
	75
	76	void skipjack_init(skipjack_ctx k, const void buf, size_t sz)
	77	{
fe371977	78	const octet *b = buf;
fe371977	79	uint32 crud;
6a0a5bdc	80	KSZ_ASSERT(skipjack, sz);
fe371977	81	k->ka = LOAD32(b);
	82	k->kb = LOAD32(b + 4);
	83	crud = LOAD16(b + 8);
	84	k->kc = U32((crud << 16) \| (k->ka >> 16));
	85	k->kd = U32((k->ka << 16) \| (k->kb >> 16));
	86	k->ke = U32((k->kb << 16) \| crud);
	87	crud = 0;
6a0a5bdc	88	}
	89
	90	/* --- @skipjack_eblk@, @skipjack_dblk@ --- *
	91	*
	92	* Arguments: @const skipjack_ctx *k@ = pointer to key block
	93	* @const uint32 s[2]@ = pointer to source block
	94	* @uint32 d[2]@ = pointer to skipjacktination block
	95	*
	96	* Returns: ---
	97	*
	98	* Use: Low-level block encryption and decryption.
	99	*/
	100
fe371977	101	#define G(x, k) do { \
6a0a5bdc	102	octet _x = U8(x >> 8), _y = U8(x); \
fe371977	103	_x ^= f[_y ^ U8(k >> 24)]; \
	104	_y ^= f[_x ^ U8(k >> 16)]; \
	105	_x ^= f[_y ^ U8(k >> 8)]; \
	106	_y ^= f[_x ^ U8(k >> 0)]; \
	107	x = (_x << 8) \| _y; \
6a0a5bdc	108	} while (0)
6a0a5bdc	109
fe371977	110	#define RULE_A(w, x, y, z, n, k) do { \
fe371977	111	G(w, k); z ^= w ^ n++; \
6a0a5bdc	112	} while (0)
6a0a5bdc	113
fe371977	114	#define RULE_B(w, x, y, z, n, k) do { \
fe371977	115	x ^= w ^ n++; G(w, k); \
6a0a5bdc	116	} while (0)
	117
	118	void skipjack_eblk(const skipjack_ctx k, const uint32 s, uint32 *d)
	119	{
6a0a5bdc	120	unsigned n = 1;
	121	uint16 w = U16(s[0] >> 16), x = U16(s[0]);
	122	uint16 y = U16(s[1] >> 16), z = U16(s[1]);
fe371977	123	uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;
	124
	125	RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
	126	RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
	127	RULE_A(w, x, y, z, n, ke); RULE_A(z, w, x, y, n, ka);
	128	RULE_A(y, z, w, x, n, kb); RULE_A(x, y, z, w, n, kc);
	129	RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
	130	RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);
	131	RULE_B(w, x, y, z, n, kc); RULE_B(z, w, x, y, n, kd);
	132	RULE_B(y, z, w, x, n, ke); RULE_B(x, y, z, w, n, ka);
	133	RULE_A(w, x, y, z, n, kb); RULE_A(z, w, x, y, n, kc);
	134	RULE_A(y, z, w, x, n, kd); RULE_A(x, y, z, w, n, ke);
	135	RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb);
	136	RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd);
	137	RULE_B(w, x, y, z, n, ke); RULE_B(z, w, x, y, n, ka);
	138	RULE_B(y, z, w, x, n, kb); RULE_B(x, y, z, w, n, kc);
	139	RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke);
	140	RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb);
6a0a5bdc	141
	142	d[0] = ((uint32)w << 16) \| (uint32)x;
	143	d[1] = ((uint32)y << 16) \| (uint32)z;
	144	}
	145
fe371977	146	#define G_INV(x, k) do { \
6a0a5bdc	147	octet _x = U8(x >> 8), _y = U8(x); \
fe371977	148	_y ^= f[_x ^ U8(k >> 0)]; \
	149	_x ^= f[_y ^ U8(k >> 8)]; \
	150	_y ^= f[_x ^ U8(k >> 16)]; \
	151	_x ^= f[_y ^ U8(k >> 24)]; \
	152	x = (_x << 8) \| _y; \
6a0a5bdc	153	} while (0)
	154
	155	#define RULE_A_INV(w, x, y, z, n, i) do { \
	156	w ^= x ^ --n; G_INV(x, i); \
	157	} while (0)
	158
	159	#define RULE_B_INV(w, x, y, z, n, i) do { \
	160	G_INV(x, i); y ^= x ^ --n; \
	161	} while (0)
	162
	163	void skipjack_dblk(const skipjack_ctx k, const uint32 s, uint32 *d)
	164	{
6a0a5bdc	165	unsigned n = 33;
	166	uint16 w = U16(s[0] >> 16), x = U16(s[0]);
	167	uint16 y = U16(s[1] >> 16), z = U16(s[1]);
fe371977	168	uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke;
	169
	170	RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
	171	RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
	172	RULE_B_INV(w, x, y, z, n, kc); RULE_B_INV(x, y, z, w, n, kb);
	173	RULE_B_INV(y, z, w, x, n, ka); RULE_B_INV(z, w, x, y, n, ke);
	174	RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
	175	RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);
	176	RULE_A_INV(w, x, y, z, n, ke); RULE_A_INV(x, y, z, w, n, kd);
	177	RULE_A_INV(y, z, w, x, n, kc); RULE_A_INV(z, w, x, y, n, kb);
	178	RULE_B_INV(w, x, y, z, n, ka); RULE_B_INV(x, y, z, w, n, ke);
	179	RULE_B_INV(y, z, w, x, n, kd); RULE_B_INV(z, w, x, y, n, kc);
	180	RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka);
	181	RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd);
	182	RULE_A_INV(w, x, y, z, n, kc); RULE_A_INV(x, y, z, w, n, kb);
	183	RULE_A_INV(y, z, w, x, n, ka); RULE_A_INV(z, w, x, y, n, ke);
	184	RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc);
	185	RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka);
6a0a5bdc	186
	187	d[0] = ((uint32)w << 16) \| (uint32)x;
	188	d[1] = ((uint32)y << 16) \| (uint32)z;
	189	}
	190
	191	BLKC_TEST(SKIPJACK, skipjack)
	192
	193	/----- That's all, folks -------------------------------------------------/