+++ /dev/null
-/* -*-c-*-
- *
- * $Id: cfb-def.h,v 1.6 2004/04/17 09:58:37 mdw Exp $
- *
- * Definitions for ciphertext 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.
- */
-
-#ifndef CATACOMB_CFB_DEF_H
-#define CATACOMB_CFB_DEF_H
-
-#ifdef __cplusplus
- extern "C" {
-#endif
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <string.h>
-
-#include <mLib/bits.h>
-#include <mLib/sub.h>
-
-#ifndef CATACOMB_ARENA_H
-# include "arena.h"
-#endif
-
-#ifndef CATACOMB_BLKC_H
-# include "blkc.h"
-#endif
-
-#ifndef CATACOMB_GCIPHER_H
-# include "gcipher.h"
-#endif
-
-#ifndef CATACOMB_PARANOIA_H
-# include "paranoia.h"
-#endif
-
-#ifndef CATACOMB_PARANOIA_H
-# include "paranoia.h"
-#endif
-
-/*----- Macros ------------------------------------------------------------*/
-
-/* --- @CFB_DEF@ --- *
- *
- * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
- *
- * Use: Creates an implementation for CFB mode.
- */
-
-#define CFB_DEF(PRE, pre) \
- \
-/* --- @pre_cfbgetiv@ --- * \
- * \
- * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB 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##_cfbgetiv(const pre##_cfbctx *ctx, void *iv) \
-{ \
- octet *p = iv; \
- unsigned off = ctx->off; \
- unsigned rest = PRE##_BLKSZ - off; \
- memcpy(p, ctx->iv + off, rest); \
- memcpy(p + rest, ctx->iv, off); \
-} \
- \
-/* --- @pre_cfbsetiv@ --- * \
- * \
- * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
- * @cnost void *iv@ = pointer to IV to set \
- * \
- * Returns: --- \
- * \
- * Use: Sets the IV to use for subsequent encryption. \
- */ \
- \
-void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \
-{ \
- memcpy(ctx->iv, iv, PRE##_BLKSZ); \
- ctx->off = PRE##_BLKSZ; \
-} \
- \
-/* --- @pre_cfbbdry@ --- * \
- * \
- * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
- * \
- * Returns: --- \
- * \
- * Use: Inserts a boundary during encryption. Successful \
- * decryption must place a similar boundary. \
- */ \
- \
-void pre##_cfbbdry(pre##_cfbctx *ctx) \
-{ \
- uint32 niv[PRE##_BLKSZ / 4]; \
- BLKC_LOAD(PRE, niv, ctx->iv); \
- pre##_eblk(&ctx->ctx, niv, niv); \
- BLKC_STORE(PRE, ctx->iv, niv); \
- ctx->off = PRE##_BLKSZ; \
- BURN(niv); \
-} \
- \
-/* --- @pre_cfbsetkey@ --- * \
- * \
- * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
- * @const pre_ctx *k@ = pointer to cipher context \
- * \
- * Returns: --- \
- * \
- * Use: Sets the CFB context to use a different cipher key. \
- */ \
- \
-void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \
-{ \
- ctx->ctx = *k; \
- ctx->off = PRE##_BLKSZ; \
-} \
- \
-/* --- @pre_cfbinit@ --- * \
- * \
- * Arguments: @pre_cfbctx *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 CFB context ready for use. You should \
- * ensure that the IV chosen is unique: reusing an IV will \
- * compromise the security of at least the first block \
- * encrypted. This is equivalent to calls to @pre_init@, \
- * @pre_cfbsetkey@ and @pre_cfbsetiv@. \
- */ \
- \
-void pre##_cfbinit(pre##_cfbctx *ctx, \
- const void *key, size_t sz, \
- const void *iv) \
-{ \
- static const octet zero[PRE##_BLKSZ] = { 0 }; \
- pre##_init(&ctx->ctx, key, sz); \
- pre##_cfbsetiv(ctx, iv ? iv : zero); \
-} \
- \
-/* --- @pre_cfbencrypt@ --- * \
- * \
- * Arguments: @pre_cfbctx *ctx@ = pointer to CFB 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 a block with a block cipher in CFB mode. The \
- * input block may be arbitrary in size. CFB mode is not \
- * sensitive to block boundaries. \
- */ \
- \
-void pre##_cfbencrypt(pre##_cfbctx *ctx, \
- const void *src, void *dest, \
- size_t sz) \
-{ \
- const octet *s = src; \
- octet *d = dest; \
- unsigned 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 --- */ \
- \
- while (off < PRE##_BLKSZ) { \
- register octet x = *s++; \
- ctx->iv[off] ^= x; \
- if (d) *d++ = ctx->iv[off]; \
- off++; \
- 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 (s) { \
- BLKC_XLOAD(PRE, iv, s); \
- s += PRE##_BLKSZ; \
- } \
- if (d) { \
- BLKC_STORE(PRE, d, iv); \
- d += PRE##_BLKSZ; \
- } \
- sz -= PRE##_BLKSZ; \
- } \
- off = 0; \
- BLKC_STORE(PRE, ctx->iv, iv); \
- } \
- \
- /* --- Tidying up the tail end --- */ \
- \
- if (sz) { \
- small: \
- do { \
- register octet x = *s++; \
- ctx->iv[off] ^= x; \
- if (d) *d++ = ctx->iv[off]; \
- off++; \
- sz--; \
- } while (sz); \
- } \
- \
- /* --- Done --- */ \
- \
- ctx->off = off; \
- return; \
-} \
- \
-/* --- @pre_cfbdecrypt@ --- * \
- * \
- * Arguments: @pre_cfbctx *ctx@ = pointer to CFB 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: Decrypts a block with a block cipher in CFB mode. The \
- * input block may be arbitrary in size. CFB mode is not \
- * sensitive to block boundaries. \
- */ \
- \
-void pre##_cfbdecrypt(pre##_cfbctx *ctx, \
- const void *src, void *dest, \
- size_t sz) \
-{ \
- const octet *s = src; \
- octet *d = dest; \
- unsigned 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 --- */ \
- \
- while (off < PRE##_BLKSZ) { \
- register octet x = *s++; \
- *d++ = ctx->iv[off] ^ x; \
- ctx->iv[off++] = x; \
- sz--; \
- } \
- \
- /* --- Main encryption loop --- */ \
- \
- { \
- uint32 iv[PRE##_BLKSZ / 4]; \
- BLKC_LOAD(PRE, iv, ctx->iv); \
- \
- for (;;) { \
- uint32 x[PRE##_BLKSZ / 4]; \
- pre##_eblk(&ctx->ctx, iv, iv); \
- if (sz < PRE##_BLKSZ) \
- break; \
- BLKC_LOAD(PRE, x, s); \
- BLKC_XSTORE(PRE, d, iv, x); \
- BLKC_MOVE(PRE, iv, x); \
- s += PRE##_BLKSZ; \
- d += PRE##_BLKSZ; \
- sz -= PRE##_BLKSZ; \
- } \
- off = 0; \
- BLKC_STORE(PRE, ctx->iv, iv); \
- } \
- \
- /* --- Tidying up the tail end --- */ \
- \
- if (sz) { \
- small: \
- do { \
- register octet x = *s++; \
- *d++ = ctx->iv[off] ^ x; \
- 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##_cfbctx k; \
-} gctx; \
- \
-static gcipher *ginit(const void *k, size_t sz) \
-{ \
- gctx *g = S_CREATE(gctx); \
- g->c.ops = &gops; \
- pre##_cfbinit(&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##_cfbencrypt(&g->k, s, t, sz); \
-} \
- \
-static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \
-{ \
- gctx *g = (gctx *)c; \
- pre##_cfbdecrypt(&g->k, s, t, sz); \
-} \
- \
-static void gdestroy(gcipher *c) \
-{ \
- gctx *g = (gctx *)c; \
- BURN(*g); \
- S_DESTROY(g); \
-} \
- \
-static void gsetiv(gcipher *c, const void *iv) \
-{ \
- gctx *g = (gctx *)c; \
- pre##_cfbsetiv(&g->k, iv); \
-} \
- \
-static void gbdry(gcipher *c) \
-{ \
- gctx *g = (gctx *)c; \
- pre##_cfbbdry(&g->k); \
-} \
- \
-static const gcipher_ops gops = { \
- &pre##_cfb, \
- gencrypt, gdecrypt, gdestroy, gsetiv, gbdry \
-}; \
- \
-const gccipher pre##_cfb = { \
- #pre "-cfb", pre##_keysz, PRE##_BLKSZ, \
- ginit \
-}; \
- \
-CFB_TEST(PRE, pre)
-
-/*----- Test rig ----------------------------------------------------------*/
-
-#ifdef TEST_RIG
-
-#include <stdio.h>
-
-#include "daftstory.h"
-
-/* --- @CFB_TEST@ --- *
- *
- * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
- *
- * Use: Standard test rig for CFB functions.
- */
-
-#define CFB_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##_cfbctx ctx; \
- int status = 0; \
- int done = 0; \
- pre##_ctx k; \
- \
- size_t keysz = PRE##_KEYSZ ? \
- PRE##_KEYSZ : strlen((const char *)key); \
- \
- fputs(#pre "-cfb: ", stdout); \
- \
- pre##_init(&k, key, keysz); \
- pre##_cfbsetkey(&ctx, &k); \
- \
- while (sz <= sizeof(text)) { \
- rest = sizeof(text) - sz; \
- memcpy(ct, text, sizeof(text)); \
- pre##_cfbsetiv(&ctx, iv); \
- pre##_cfbencrypt(&ctx, ct, ct, sz); \
- pre##_cfbencrypt(&ctx, ct + sz, ct + sz, rest); \
- memcpy(pt, ct, sizeof(text)); \
- pre##_cfbsetiv(&ctx, iv); \
- pre##_cfbdecrypt(&ctx, pt, pt, rest); \
- pre##_cfbdecrypt(&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 CFB_TEST(PRE, pre)
-#endif
-
-/*----- That's all, folks -------------------------------------------------*/
-
-#ifdef __cplusplus
- }
-#endif
-
-#endif
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