--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: cfb-def.h,v 1.1 1999/12/10 23:16:39 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.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: cfb-def.h,v $
+ * Revision 1.1 1999/12/10 23:16:39 mdw
+ * Split mode macros into interface and implementation.
+ *
+ */
+
+#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_BLKC_H
+# include "blkc.h"
+#endif
+
+#ifndef CATACOMB_GCIPHER_H
+# include "gcipher.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; \
+ int off = ctx->off; \
+ int 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) \
+{ \
+ 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_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) \
+{ \
+ octet iv[PRE##_BLKSZ]; \
+ pre##_cfbgetiv(ctx, iv); \
+ pre##_cfbsetiv(ctx, iv); \
+ BURN(iv); \
+} \
+ \
+/* --- @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; \
+} \
+ \
+/* --- @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 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; \
+ 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 --- */ \
+ \
+ while (off < PRE##_BLKSZ) { \
+ register octet x = *s++; \
+ *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; \
+ BLKC_XLOAD(PRE, iv, s); \
+ BLKC_STORE(PRE, d, iv); \
+ 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; \
+ sz--; \
+ } while (sz); \
+ } \
+ \
+ /* --- Done --- */ \
+ \
+ ctx->off = off; \
+ return; \
+} \
+ \
+/* --- @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: 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; \
+ 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 --- */ \
+ \
+ 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 = 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; \
+ 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.b, \
+ 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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