[u/mdw/catacomb] / ofb-def.h

/* -*-c-*-
 *
 * $Id: ofb-def.h,v 1.2 1999/12/13 15:34:01 mdw Exp $
 *
 * Definitions for output feedback mode
 *
 * (c) 1999 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: ofb-def.h,v $
 * Revision 1.2  1999/12/13 15:34:01  mdw
 * Add support for seeding from a generic pseudorandom source.
 *
 * Revision 1.1  1999/12/10 23:16:40  mdw
 * Split mode macros into interface and implementation.
 *
 */

#ifndef CATACOMB_OFB_DEF_H
#define CATACOMB_OFB_DEF_H

#ifdef __cplusplus
  extern "C" {
#endif

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

#include <stdarg.h>
#include <string.h>

#include <mLib/bits.h>
#include <mLib/sub.h>

#ifndef CATACOMB_BLKC_H
#  include "blkc.h"
#endif

#ifndef CATACOMB_GCIPHER_H
#  include "gcipher.h"
#endif

#ifndef CATACOMB_PARANOIA_H
#  include "paranoia.h"
#endif

/*----- Macros ------------------------------------------------------------*/

/* --- @OFB_DEF@ --- *
 *
 * Arguments:	@PRE@, @pre@ = prefixes for the underlying block cipher
 *
 * Use:		Creates definitions for output feedback mode.
 */

#define OFB_DEF(PRE, pre)						\
									\
/* --- @pre_ofbgetiv@ --- *						\
 *									\
 * Arguments:	@const pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@void *iv#@ = pointer to output data block		\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Reads the currently set IV.  Reading and setting an IV	\
 *		is not transparent to the cipher.  It will add a `step'	\
 *		which must be matched by a similar operation during	\
 *		decryption.						\
 */									\
									\
void pre##_ofbgetiv(const pre##_ofbctx *ctx, void *iv)			\
{									\
  octet *p = iv;							\
  int off = ctx->off;							\
  int rest = PRE##_BLKSZ - off;						\
  memcpy(p, ctx->iv + off, rest);					\
  memcpy(p + rest, ctx->iv, off);					\
}									\
									\
/* --- @pre_ofbsetiv@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@cnost void *iv@ = pointer to IV to set			\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Sets the IV to use for subsequent encryption.		\
 */									\
									\
void pre##_ofbsetiv(pre##_ofbctx *ctx, const void *iv)			\
{									\
  uint32 niv[PRE##_BLKSZ / 4];						\
  BLKC_LOAD(PRE, niv, iv);						\
  pre##_eblk(&ctx->ctx, niv, niv);					\
  BLKC_STORE(PRE, ctx->iv, niv);					\
  ctx->off = 0;								\
}									\
									\
/* --- @pre_ofbbdry@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Inserts a boundary during encryption.  Successful	\
 *		decryption must place a similar boundary.		\
 */									\
									\
void pre##_ofbbdry(pre##_ofbctx *ctx)					\
{									\
  octet iv[PRE##_BLKSZ];						\
  pre##_ofbgetiv(ctx, iv);						\
  pre##_ofbsetiv(ctx, iv);						\
  BURN(iv);								\
}									\
									\
/* --- @pre_ofbsetkey@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@const pre_ctx *k@ = pointer to cipher context		\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Sets the OFB context to use a different cipher key.	\
 */									\
									\
void pre##_ofbsetkey(pre##_ofbctx *ctx, const pre##_ctx *k)		\
{									\
  ctx->ctx = *k;							\
}									\
									\
/* --- @pre_ofbinit@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to cipher context		\
 *		@const void *key@ = pointer to the key buffer		\
 *		@size_t sz@ = size of the key				\
 *		@const void *iv@ = pointer to initialization vector	\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Initializes a OFB context ready for use.  You should	\
 *		ensure that the IV chosen is unique: reusing an IV will	\
 *		compromise the security of the entire plaintext.  This	\
 *		is equivalent to calls to @pre_init@, @pre_ofbsetkey@	\
 *		and @pre_ofbsetiv@.					\
 */									\
									\
void pre##_ofbinit(pre##_ofbctx *ctx,					\
		     const void *key, size_t sz,			\
		     const void *iv)					\
{									\
  static octet zero[PRE##_BLKSZ] = { 0 };				\
  pre##_init(&ctx->ctx, key, sz);					\
  pre##_ofbsetiv(ctx, iv ? iv : zero);					\
}									\
									\
/* --- @pre_ofbencrypt@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@const void *src@ = pointer to source data		\
 *		@void *dest@ = pointer to destination data		\
 *		@size_t sz@ = size of block to be encrypted		\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Encrypts or decrypts a block with a block cipher in OFB	\
 *		mode: encryption and decryption are the same in OFB.	\
 *		The destination may be null to just churn the feedback	\
 *		round for a bit.  The source may be null to use the	\
 *		cipher as a random data generator.			\
 */									\
									\
void pre##_ofbencrypt(pre##_ofbctx *ctx,				\
			const void *src, void *dest,			\
			size_t sz)					\
{									\
  const octet *s = src;							\
  octet *d = dest;							\
  int off = ctx->off;							\
									\
  /* --- Empty blocks are trivial --- */				\
									\
  if (!sz)								\
    return;								\
									\
  /* --- If I can deal with the block from my buffer, do that --- */	\
									\
  if (sz < PRE##_BLKSZ - off)						\
    goto small;								\
									\
  /* --- Finish off what's left in my buffer --- */			\
									\
  if (!d)								\
    sz -= off;								\
  else {								\
    while (off < PRE##_BLKSZ) {						\
      register octet x = s ? *s++ : 0;					\
      *d++ = ctx->iv[off++] ^ x;					\
      sz--;								\
    }									\
  }									\
									\
  /* --- Main encryption loop --- */					\
									\
  {									\
    uint32 iv[PRE##_BLKSZ / 4];						\
    BLKC_LOAD(PRE, iv, ctx->iv);					\
									\
    for (;;) {								\
      pre##_eblk(&ctx->ctx, iv, iv);					\
      if (sz < PRE##_BLKSZ)						\
	break;								\
      if (d) {								\
	if (!s)								\
	  BLKC_STORE(PRE, d, iv);					\
	else {								\
	  uint32 x[PRE##_BLKSZ / 4];					\
	  BLKC_LOAD(PRE, x, s);						\
	  BLKC_XSTORE(PRE, d, iv, x);					\
	  s += PRE##_BLKSZ;						\
	}								\
	d += PRE##_BLKSZ;						\
      }									\
      sz -= PRE##_BLKSZ;						\
    }									\
									\
    BLKC_STORE(PRE, ctx->iv, iv);					\
    off = 0;								\
  }									\
									\
  /* --- Tidying up the tail end --- */					\
									\
  if (sz) {								\
  small:								\
    if (!d)								\
      off += sz;							\
    else do {								\
      register octet x = s ? *s++ : 0;					\
      *d++ = ctx->iv[off++] ^ x;					\
      sz--;								\
    } while (sz);							\
  }									\
									\
  /* --- Done --- */							\
									\
  ctx->off = off;							\
  return;								\
}									\
									\
/* --- Generic cipher interface --- */					\
									\
static const gcipher_ops gops;						\
									\
typedef struct gctx {							\
  gcipher c;								\
  pre##_ofbctx k;							\
} gctx;									\
									\
static gcipher *ginit(const void *k, size_t sz)				\
{									\
  gctx *g = CREATE(gctx);						\
  g->c.ops = &gops;							\
  pre##_ofbinit(&g->k, k, sz, 0);					\
  return (&g->c);							\
}									\
									\
static void gencrypt(gcipher *c, const void *s, void *t, size_t sz)	\
{									\
  gctx *g = (gctx *)c;							\
  pre##_ofbencrypt(&g->k, s, t, sz);					\
}									\
									\
static void gdestroy(gcipher *c)					\
{									\
  gctx *g = (gctx *)c;							\
  DESTROY(g);								\
}									\
									\
static void gsetiv(gcipher *c, const void *iv)				\
{									\
  gctx *g = (gctx *)c;							\
  pre##_ofbsetiv(&g->k, iv);						\
}									\
									\
static void gbdry(gcipher *c)						\
{									\
  gctx *g = (gctx *)c;							\
  pre##_ofbbdry(&g->k);							\
}									\
									\
static const gcipher_ops gops = {					\
  &pre##_ofb.b,								\
  gencrypt, gencrypt, gdestroy, gsetiv, gbdry				\
};									\
									\
const gccipher pre##_ofb = {						\
  { #pre "-ofb", PRE##_KEYSZ, PRE##_BLKSZ },				\
  ginit									\
};									\
									\
/* --- Generic random number generator interface --- */			\
									\
typedef struct grctx {							\
  grand r;								\
  pre##_ofbctx k;							\
} grctx;								\
									\
static void grdestroy(grand *r)						\
{									\
  grctx *g = (grctx *)r;						\
  DESTROY(g);								\
}									\
									\
static int grmisc(grand *r, unsigned op, ...)				\
{									\
  grctx *g = (grctx *)r;						\
  va_list ap;								\
  int rc = 0;								\
  octet buf[PRE##_BLKSZ];						\
  va_start(ap, op);							\
									\
  switch (op) {								\
    case GRAND_CHECK:							\
      switch (va_arg(ap, unsigned)) {					\
	case GRAND_CHECK:						\
	case GRAND_SEEDINT:						\
	case GRAND_SEEDUINT32:						\
	case GRAND_SEEDBLOCK:						\
	case GRAND_SEEDRAND:						\
	  rc = 1;							\
	  break;							\
	default:							\
	  rc = 0;							\
	  break;							\
      }									\
      break;								\
    case GRAND_SEEDINT:							\
      memset(buf, 0, sizeof(buf));					\
      STORE32(buf, va_arg(ap, unsigned));				\
      pre##_ofbsetiv(&g->k, buf);					\
      break;								\
    case GRAND_SEEDUINT32:						\
      memset(buf, 0, sizeof(buf));					\
      STORE32(buf, va_arg(ap, uint32));					\
      pre##_ofbsetiv(&g->k, buf);					\
      break;								\
    case GRAND_SEEDBLOCK: {						\
      const void *p = va_arg(ap, const void *);				\
      size_t sz = va_arg(ap, size_t);					\
      if (sz < sizeof(buf)) {						\
	memset(buf, 0, sizeof(buf));					\
	memcpy(buf, p, sz);						\
	p = buf;							\
      }									\
      pre##_ofbsetiv(&g->k, p);						\
    } break;								\
    case GRAND_SEEDRAND: {						\
      grand *rr = va_arg(ap, grand *);					\
      rr->ops->fill(rr, buf, sizeof(buf));				\
      pre##_ofbsetiv(&g->k, buf);					\
    } break;								\
    default:								\
      GRAND_BADOP;							\
      break;								\
  }									\
									\
  va_end(ap);								\
  return (rc);								\
}									\
									\
static octet grbyte(grand *r)						\
{									\
  grctx *g = (grctx *)r;						\
  octet o;								\
  pre##_ofbencrypt(&g->k, 0, &o, 1);					\
  return (o);								\
}									\
									\
static uint32 grword(grand *r)						\
{									\
  grctx *g = (grctx *)r;						\
  octet b[4];								\
  pre##_ofbencrypt(&g->k, 0, b, sizeof(b));				\
  return (LOAD32(b));							\
}									\
									\
static void grfill(grand *r, void *p, size_t sz)			\
{									\
  grctx *g = (grctx *)r;						\
  pre##_ofbencrypt(&g->k, 0, p, sz);					\
}									\
									\
static const grand_ops grops = {					\
  #pre "-ofb",								\
  0,									\
  grmisc, grdestroy,							\
  grword, grbyte, grword, grand_range, grfill				\
};									\
									\
/* --- @pre_ofbrand@ --- *						\
 *									\
 * Arguments:	@const void *k@ = pointer to key material		\
 *		@size_t sz@ = size of key material			\
 *									\
 * Returns:	Pointer to generic random number generator interface.	\
 *									\
 * Use:		Creates a random number interface wrapper around an	\
 *		OFB-mode block cipher.					\
 */									\
									\
grand *pre##_ofbrand(const void *k, size_t sz)				\
{									\
  grctx *g = CREATE(grctx);						\
  g->r.ops = &grops;							\
  pre##_ofbinit(&g->k, k, sz, 0);					\
  return (&g->r);							\
}									\
									\
OFB_TEST(PRE, pre)

/*----- Test rig ----------------------------------------------------------*/

#ifdef TEST_RIG

#include <stdio.h>

#include "daftstory.h"

/* --- @OFB_TEST@ --- *
 *
 * Arguments:	@PRE@, @pre@ = prefixes for block cipher definitions
 *
 * Use:		Standard test rig for OFB functions.
 */

#define OFB_TEST(PRE, pre)						\
									\
/* --- Initial plaintext for the test --- */				\
									\
static const octet text[] = TEXT;					\
									\
/* --- Key and IV to use --- */						\
									\
static const octet key[] = KEY;						\
static const octet iv[] = IV;						\
									\
/* --- Buffers for encryption and decryption output --- */		\
									\
static octet ct[sizeof(text)];						\
static octet pt[sizeof(text)];						\
									\
static void hexdump(const octet *p, size_t sz)				\
{									\
  const octet *q = p + sz;						\
  for (sz = 0; p < q; p++, sz++) {					\
    printf("%02x", *p);							\
    if ((sz + 1) % PRE##_BLKSZ == 0)					\
      putchar(':');							\
  }									\
}									\
									\
int main(void)								\
{									\
  size_t sz = 0, rest;							\
  pre##_ofbctx ctx;							\
  int status = 0;							\
  int done = 0;								\
  pre##_ctx k;								\
									\
  size_t keysz = PRE##_KEYSZ ?						\
    PRE##_KEYSZ : strlen((const char *)key);				\
									\
  fputs(#pre "-ofb: ", stdout);						\
									\
  pre##_init(&k, key, keysz);						\
  pre##_ofbsetkey(&ctx, &k);						\
									\
  while (sz <= sizeof(text)) {						\
    rest = sizeof(text) - sz;						\
    memcpy(ct, text, sizeof(text));					\
    pre##_ofbsetiv(&ctx, iv);						\
    pre##_ofbencrypt(&ctx, ct, ct, sz);					\
    pre##_ofbencrypt(&ctx, ct + sz, ct + sz, rest);			\
    memcpy(pt, ct, sizeof(text));					\
    pre##_ofbsetiv(&ctx, iv);						\
    pre##_ofbencrypt(&ctx, pt, pt, rest);				\
    pre##_ofbencrypt(&ctx, pt + rest, pt + rest, sz);			\
    if (memcmp(pt, text, sizeof(text)) == 0) {				\
      done++;								\
      if (sizeof(text) < 40 || done % 8 == 0)				\
        fputc('.', stdout);						\
      if (done % 480 == 0)						\
        fputs("\n\t", stdout);						\
      fflush(stdout);							\
    } else {								\
      printf("\nError (sz = %lu)\n", (unsigned long)sz);		\
      status = 1;							\
      printf("\tplaintext      = "); hexdump(text, sz);			\
        printf(", "); hexdump(text + sz, rest);				\
        fputc('\n', stdout);						\
      printf("\tciphertext     = "); hexdump(ct, sz);			\
        printf(", "); hexdump(ct + sz, rest);				\
        fputc('\n', stdout);						\
      printf("\trecovered text = "); hexdump(pt, sz);			\
        printf(", "); hexdump(pt + sz, rest);				\
        fputc('\n', stdout);						\
      fputc('\n', stdout);						\
    }									\
    if (sz < 63)							\
      sz++;								\
    else								\
      sz += 9;								\
  }									\
									\
  fputs(status ? " failed\n" : " ok\n", stdout);			\
  return (status);							\
}

#else
#  define OFB_TEST(PRE, pre)
#endif

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif
Commit	Line	Data
79ba130c	1	/* --c--
79ba130c	2	*
4ab1268f	3	* $Id: ofb-def.h,v 1.2 1999/12/13 15:34:01 mdw Exp $
79ba130c	4	*
	5	* Definitions for output feedback mode
	6	*
	7	* (c) 1999 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: ofb-def.h,v $
4ab1268f	33	* Revision 1.2 1999/12/13 15:34:01 mdw
	34	* Add support for seeding from a generic pseudorandom source.
	35	*
79ba130c	36	* Revision 1.1 1999/12/10 23:16:40 mdw
	37	* Split mode macros into interface and implementation.
	38	*
	39	*/
	40
	41	#ifndef CATACOMB_OFB_DEF_H
	42	#define CATACOMB_OFB_DEF_H
	43
	44	#ifdef __cplusplus
	45	extern "C" {
	46	#endif
	47
	48	/----- Header files ------------------------------------------------------/
	49
	50	#include <stdarg.h>
	51	#include <string.h>
	52
	53	#include <mLib/bits.h>
	54	#include <mLib/sub.h>
	55
	56	#ifndef CATACOMB_BLKC_H
	57	# include "blkc.h"
	58	#endif
	59
	60	#ifndef CATACOMB_GCIPHER_H
	61	# include "gcipher.h"
	62	#endif
	63
	64	#ifndef CATACOMB_PARANOIA_H
	65	# include "paranoia.h"
	66	#endif
	67
	68	/----- Macros ------------------------------------------------------------/
	69
	70	/* --- @OFB_DEF@ --- *
	71	*
	72	* Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
	73	*
	74	* Use: Creates definitions for output feedback mode.
	75	*/
	76
	77	#define OFB_DEF(PRE, pre) \
	78	\
	79	/* --- @pre_ofbgetiv@ --- * \
	80	* \
	81	* Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \
	82	* @void *iv#@ = pointer to output data block \
	83	* \
	84	* Returns: --- \
	85	* \
	86	* Use: Reads the currently set IV. Reading and setting an IV \
	87	* is not transparent to the cipher. It will add a `step' \
	88	* which must be matched by a similar operation during \
	89	* decryption. \
	90	*/ \
	91	\
	92	void pre##_ofbgetiv(const pre##_ofbctx ctx, void iv) \
	93	{ \
	94	octet *p = iv; \
	95	int off = ctx->off; \
	96	int rest = PRE##_BLKSZ - off; \
	97	memcpy(p, ctx->iv + off, rest); \
	98	memcpy(p + rest, ctx->iv, off); \
	99	} \
100	\
101	/* --- @pre_ofbsetiv@ --- * \
102	* \
103	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
104	* @cnost void *iv@ = pointer to IV to set \
105	* \
106	* Returns: --- \
107	* \
108	* Use: Sets the IV to use for subsequent encryption. \
109	*/ \
110	\
111	void pre##_ofbsetiv(pre##_ofbctx ctx, const void iv) \
112	{ \
113	uint32 niv[PRE##_BLKSZ / 4]; \
114	BLKC_LOAD(PRE, niv, iv); \
115	pre##_eblk(&ctx->ctx, niv, niv); \
116	BLKC_STORE(PRE, ctx->iv, niv); \
117	ctx->off = 0; \
118	} \
119	\
120	/* --- @pre_ofbbdry@ --- * \
121	* \
122	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
123	* \
124	* Returns: --- \
125	* \
126	* Use: Inserts a boundary during encryption. Successful \
127	* decryption must place a similar boundary. \
128	*/ \
129	\
130	void pre##_ofbbdry(pre##_ofbctx *ctx) \
131	{ \
132	octet iv[PRE##_BLKSZ]; \
133	pre##_ofbgetiv(ctx, iv); \
134	pre##_ofbsetiv(ctx, iv); \
135	BURN(iv); \
136	} \
137	\
138	/* --- @pre_ofbsetkey@ --- * \
139	* \
140	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
141	* @const pre_ctx *k@ = pointer to cipher context \
142	* \
143	* Returns: --- \
144	* \
145	* Use: Sets the OFB context to use a different cipher key. \
146	*/ \
147	\
148	void pre##_ofbsetkey(pre##_ofbctx ctx, const pre##_ctx k) \
149	{ \
150	ctx->ctx = *k; \
151	} \
152	\
153	/* --- @pre_ofbinit@ --- * \
154	* \
155	* Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \
156	* @const void *key@ = pointer to the key buffer \
157	* @size_t sz@ = size of the key \
158	* @const void *iv@ = pointer to initialization vector \
159	* \
160	* Returns: --- \
161	* \
162	* Use: Initializes a OFB context ready for use. You should \
163	* ensure that the IV chosen is unique: reusing an IV will \
164	* compromise the security of the entire plaintext. This \
165	* is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \
166	* and @pre_ofbsetiv@. \
167	*/ \
168	\
169	void pre##_ofbinit(pre##_ofbctx *ctx, \
170	const void *key, size_t sz, \
171	const void *iv) \
172	{ \
173	static octet zero[PRE##_BLKSZ] = { 0 }; \
174	pre##_init(&ctx->ctx, key, sz); \
175	pre##_ofbsetiv(ctx, iv ? iv : zero); \
176	} \
177	\
178	/* --- @pre_ofbencrypt@ --- * \
179	* \
180	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
181	* @const void *src@ = pointer to source data \
182	* @void *dest@ = pointer to destination data \
183	* @size_t sz@ = size of block to be encrypted \
184	* \
185	* Returns: --- \
186	* \
187	* Use: Encrypts or decrypts a block with a block cipher in OFB \
188	* mode: encryption and decryption are the same in OFB. \
189	* The destination may be null to just churn the feedback \
190	* round for a bit. The source may be null to use the \
191	* cipher as a random data generator. \
192	*/ \
193	\
194	void pre##_ofbencrypt(pre##_ofbctx *ctx, \
195	const void src, void dest, \
196	size_t sz) \
197	{ \
198	const octet *s = src; \
199	octet *d = dest; \
200	int off = ctx->off; \
201	\
202	/* --- Empty blocks are trivial --- */ \
203	\
204	if (!sz) \
205	return; \
206	\
207	/* --- If I can deal with the block from my buffer, do that --- */ \
208	\
209	if (sz < PRE##_BLKSZ - off) \
210	goto small; \
211	\
212	/* --- Finish off what's left in my buffer --- */ \
213	\
214	if (!d) \
215	sz -= off; \
216	else { \
217	while (off < PRE##_BLKSZ) { \
218	register octet x = s ? *s++ : 0; \
219	*d++ = ctx->iv[off++] ^ x; \
220	sz--; \
221	} \
222	} \
223	\
224	/* --- Main encryption loop --- */ \
225	\
226	{ \
227	uint32 iv[PRE##_BLKSZ / 4]; \
228	BLKC_LOAD(PRE, iv, ctx->iv); \
229	\
230	for (;;) { \
231	pre##_eblk(&ctx->ctx, iv, iv); \
232	if (sz < PRE##_BLKSZ) \
233	break; \
234	if (d) { \
235	if (!s) \
236	BLKC_STORE(PRE, d, iv); \
237	else { \
238	uint32 x[PRE##_BLKSZ / 4]; \
239	BLKC_LOAD(PRE, x, s); \
240	BLKC_XSTORE(PRE, d, iv, x); \
241	s += PRE##_BLKSZ; \
242	} \
243	d += PRE##_BLKSZ; \
244	} \
245	sz -= PRE##_BLKSZ; \
246	} \
247	\
248	BLKC_STORE(PRE, ctx->iv, iv); \
249	off = 0; \
250	} \
251	\
252	/* --- Tidying up the tail end --- */ \
253	\
254	if (sz) { \
255	small: \
256	if (!d) \
257	off += sz; \
258	else do { \
259	register octet x = s ? *s++ : 0; \
260	*d++ = ctx->iv[off++] ^ x; \
261	sz--; \
262	} while (sz); \
263	} \
264	\
265	/* --- Done --- */ \
266	\
267	ctx->off = off; \
268	return; \
269	} \
270	\
271	/* --- Generic cipher interface --- */ \
272	\
273	static const gcipher_ops gops; \
274	\
275	typedef struct gctx { \
276	gcipher c; \
277	pre##_ofbctx k; \
278	} gctx; \
279	\
280	static gcipher ginit(const void k, size_t sz) \
281	{ \
282	gctx *g = CREATE(gctx); \
283	g->c.ops = &gops; \
284	pre##_ofbinit(&g->k, k, sz, 0); \
285	return (&g->c); \
286	} \
287	\
288	static void gencrypt(gcipher c, const void s, void *t, size_t sz) \
289	{ \
290	gctx g = (gctx )c; \
291	pre##_ofbencrypt(&g->k, s, t, sz); \
292	} \
293	\
294	static void gdestroy(gcipher *c) \
295	{ \
296	gctx g = (gctx )c; \
297	DESTROY(g); \
298	} \
299	\
300	static void gsetiv(gcipher c, const void iv) \
301	{ \
302	gctx g = (gctx )c; \
303	pre##_ofbsetiv(&g->k, iv); \
304	} \
305	\
306	static void gbdry(gcipher *c) \
307	{ \
308	gctx g = (gctx )c; \
309	pre##_ofbbdry(&g->k); \
310	} \
311	\
312	static const gcipher_ops gops = { \
313	&pre##_ofb.b, \
314	gencrypt, gencrypt, gdestroy, gsetiv, gbdry \
315	}; \
316	\
317	const gccipher pre##_ofb = { \
318	{ #pre "-ofb", PRE##_KEYSZ, PRE##_BLKSZ }, \
319	ginit \
320	}; \
321	\
322	/* --- Generic random number generator interface --- */ \
323	\
324	typedef struct grctx { \
325	grand r; \
326	pre##_ofbctx k; \
327	} grctx; \
328	\
329	static void grdestroy(grand *r) \
330	{ \
331	grctx g = (grctx )r; \
332	DESTROY(g); \
333	} \
334	\
335	static int grmisc(grand *r, unsigned op, ...) \
336	{ \
337	grctx g = (grctx )r; \
338	va_list ap; \
339	int rc = 0; \
340	octet buf[PRE##_BLKSZ]; \
341	va_start(ap, op); \
342	\
343	switch (op) { \
344	case GRAND_CHECK: \
345	switch (va_arg(ap, unsigned)) { \
346	case GRAND_CHECK: \
347	case GRAND_SEEDINT: \
348	case GRAND_SEEDUINT32: \
349	case GRAND_SEEDBLOCK: \
4ab1268f	350	case GRAND_SEEDRAND: \
79ba130c	351	rc = 1; \
	352	break; \
	353	default: \
	354	rc = 0; \
	355	break; \
	356	} \
	357	break; \
	358	case GRAND_SEEDINT: \
	359	memset(buf, 0, sizeof(buf)); \
	360	STORE32(buf, va_arg(ap, unsigned)); \
	361	pre##_ofbsetiv(&g->k, buf); \
	362	break; \
	363	case GRAND_SEEDUINT32: \
	364	memset(buf, 0, sizeof(buf)); \
	365	STORE32(buf, va_arg(ap, uint32)); \
	366	pre##_ofbsetiv(&g->k, buf); \
	367	break; \
	368	case GRAND_SEEDBLOCK: { \
	369	const void p = va_arg(ap, const void ); \
	370	size_t sz = va_arg(ap, size_t); \
	371	if (sz < sizeof(buf)) { \
	372	memset(buf, 0, sizeof(buf)); \
	373	memcpy(buf, p, sz); \
	374	p = buf; \
	375	} \
	376	pre##_ofbsetiv(&g->k, p); \
	377	} break; \
4ab1268f	378	case GRAND_SEEDRAND: { \
	379	grand rr = va_arg(ap, grand ); \
	380	rr->ops->fill(rr, buf, sizeof(buf)); \
	381	pre##_ofbsetiv(&g->k, buf); \
	382	} break; \
	383	default: \
	384	GRAND_BADOP; \
	385	break; \
79ba130c	386	} \
	387	\
	388	va_end(ap); \
	389	return (rc); \
	390	} \
	391	\
	392	static octet grbyte(grand *r) \
	393	{ \
	394	grctx g = (grctx )r; \
	395	octet o; \
	396	pre##_ofbencrypt(&g->k, 0, &o, 1); \
	397	return (o); \
	398	} \
	399	\
	400	static uint32 grword(grand *r) \
	401	{ \
	402	grctx g = (grctx )r; \
	403	octet b[4]; \
	404	pre##_ofbencrypt(&g->k, 0, b, sizeof(b)); \
	405	return (LOAD32(b)); \
	406	} \
	407	\
	408	static void grfill(grand r, void p, size_t sz) \
	409	{ \
	410	grctx g = (grctx )r; \
	411	pre##_ofbencrypt(&g->k, 0, p, sz); \
	412	} \
	413	\
	414	static const grand_ops grops = { \
	415	#pre "-ofb", \
	416	0, \
	417	grmisc, grdestroy, \
	418	grword, grbyte, grword, grand_range, grfill \
	419	}; \
	420	\
	421	/* --- @pre_ofbrand@ --- * \
	422	* \
	423	* Arguments: @const void *k@ = pointer to key material \
	424	* @size_t sz@ = size of key material \
	425	* \
	426	* Returns: Pointer to generic random number generator interface. \
	427	* \
	428	* Use: Creates a random number interface wrapper around an \
	429	* OFB-mode block cipher. \
	430	*/ \
	431	\
	432	grand pre##_ofbrand(const void k, size_t sz) \
	433	{ \
	434	grctx *g = CREATE(grctx); \
	435	g->r.ops = &grops; \
	436	pre##_ofbinit(&g->k, k, sz, 0); \
	437	return (&g->r); \
	438	} \
	439	\
	440	OFB_TEST(PRE, pre)
	441
	442	/----- Test rig ----------------------------------------------------------/
	443
	444	#ifdef TEST_RIG
	445
	446	#include <stdio.h>
	447
	448	#include "daftstory.h"
	449
450	/* --- @OFB_TEST@ --- *
451	*
452	* Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
453	*
454	* Use: Standard test rig for OFB functions.
455	*/
456
457	#define OFB_TEST(PRE, pre) \
458	\
459	/* --- Initial plaintext for the test --- */ \
460	\
461	static const octet text[] = TEXT; \
462	\
463	/* --- Key and IV to use --- */ \
464	\
465	static const octet key[] = KEY; \
466	static const octet iv[] = IV; \
467	\
468	/* --- Buffers for encryption and decryption output --- */ \
469	\
470	static octet ct[sizeof(text)]; \
471	static octet pt[sizeof(text)]; \
472	\
473	static void hexdump(const octet *p, size_t sz) \
474	{ \
475	const octet *q = p + sz; \
476	for (sz = 0; p < q; p++, sz++) { \
477	printf("%02x", *p); \
478	if ((sz + 1) % PRE##_BLKSZ == 0) \
479	putchar(':'); \
480	} \
481	} \
482	\
483	int main(void) \
484	{ \
485	size_t sz = 0, rest; \
486	pre##_ofbctx ctx; \
487	int status = 0; \
488	int done = 0; \
489	pre##_ctx k; \
490	\
491	size_t keysz = PRE##_KEYSZ ? \
492	PRE##_KEYSZ : strlen((const char *)key); \
493	\
494	fputs(#pre "-ofb: ", stdout); \
495	\
496	pre##_init(&k, key, keysz); \
497	pre##_ofbsetkey(&ctx, &k); \
498	\
499	while (sz <= sizeof(text)) { \
500	rest = sizeof(text) - sz; \
501	memcpy(ct, text, sizeof(text)); \
502	pre##_ofbsetiv(&ctx, iv); \
503	pre##_ofbencrypt(&ctx, ct, ct, sz); \
504	pre##_ofbencrypt(&ctx, ct + sz, ct + sz, rest); \
505	memcpy(pt, ct, sizeof(text)); \
506	pre##_ofbsetiv(&ctx, iv); \
507	pre##_ofbencrypt(&ctx, pt, pt, rest); \
508	pre##_ofbencrypt(&ctx, pt + rest, pt + rest, sz); \
509	if (memcmp(pt, text, sizeof(text)) == 0) { \
510	done++; \
511	if (sizeof(text) < 40 \|\| done % 8 == 0) \
512	fputc('.', stdout); \
513	if (done % 480 == 0) \
514	fputs("\n\t", stdout); \
515	fflush(stdout); \
516	} else { \
517	printf("\nError (sz = %lu)\n", (unsigned long)sz); \
518	status = 1; \
519	printf("\tplaintext = "); hexdump(text, sz); \
520	printf(", "); hexdump(text + sz, rest); \
521	fputc('\n', stdout); \
522	printf("\tciphertext = "); hexdump(ct, sz); \
523	printf(", "); hexdump(ct + sz, rest); \
524	fputc('\n', stdout); \
525	printf("\trecovered text = "); hexdump(pt, sz); \
526	printf(", "); hexdump(pt + sz, rest); \
527	fputc('\n', stdout); \
528	fputc('\n', stdout); \
529	} \
530	if (sz < 63) \
531	sz++; \
532	else \
533	sz += 9; \
534	} \
535	\
536	fputs(status ? " failed\n" : " ok\n", stdout); \
537	return (status); \
538	}
539
540	#else
541	# define OFB_TEST(PRE, pre)
542	#endif
543
544	/----- That's all, folks -------------------------------------------------/
545
546	#ifdef __cplusplus
547	}
548	#endif
549
550	#endif