--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: cbc-def.h,v 1.1 1999/12/10 23:16:39 mdw Exp $
+ *
+ * Definitions for cipher block chaining 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: cbc-def.h,v $
+ * Revision 1.1 1999/12/10 23:16:39 mdw
+ * Split mode macros into interface and implementation.
+ *
+ */
+
+#ifndef CATACOMB_CBC_DEF_H
+#define CATACOMB_CBC_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
+
+/*----- Macros ------------------------------------------------------------*/
+
+/* --- @CBC_DEF@ --- *
+ *
+ * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
+ *
+ * Use: Creates an implementation for CBC stealing mode.
+ */
+
+#define CBC_DEF(PRE, pre) \
+ \
+/* --- @pre_cbcgetiv@ --- * \
+ * \
+ * Arguments: @const pre_cbcctx *ctx@ = pointer to CBC context block \
+ * @void *iv#@ = pointer to output data block \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Reads the currently set IV. Reading and setting an IV \
+ * is transparent to the CBC encryption or decryption \
+ * process. \
+ */ \
+ \
+void pre##_cbcgetiv(const pre##_cbcctx *ctx, void *iv) \
+{ \
+ BLKC_STORE(PRE, iv, ctx->iv); \
+} \
+ \
+/* --- @pre_cbcsetiv@ --- * \
+ * \
+ * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
+ * @cnost void *iv@ = pointer to IV to set \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Sets the IV to use for subsequent encryption. \
+ */ \
+ \
+void pre##_cbcsetiv(pre##_cbcctx *ctx, const void *iv) \
+{ \
+ BLKC_LOAD(PRE, ctx->iv, iv); \
+} \
+ \
+/* --- @pre_cbcsetkey@ --- * \
+ * \
+ * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \
+ * @const pre_ctx *k@ = pointer to cipher context \
+ * \
+ * Returns: --- \
+ * \
+ * Use: Sets the CBC context to use a different cipher key. \
+ */ \
+ \
+void pre##_cbcsetkey(pre##_cbcctx *ctx, const pre##_ctx *k) \
+{ \
+ ctx->ctx = *k; \
+} \
+ \
+/* --- @pre_cbcinit@ --- * \
+ * \
+ * Arguments: @pre_cbcctx *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 CBC context ready for use. The @iv@ \
+ * argument may be passed as a null pointer to set a zero \
+ * IV. Apart from that, this call is equivalent to calls \
+ * to @pre_init@, @pre_cbcsetkey@ and @pre_cbcsetiv@. \
+ */ \
+ \
+void pre##_cbcinit(pre##_cbcctx *ctx, \
+ const void *key, size_t sz, \
+ const void *iv) \
+{ \
+ static octet zero[PRE##_BLKSZ] = { 0 }; \
+ pre##_init(&ctx->ctx, key, sz); \
+ BLKC_LOAD(PRE, ctx->iv, iv ? iv : zero); \
+} \
+ \
+/* --- @pre_cbcencrypt@ --- * \
+ * \
+ * Arguments: @pre_cbcctx *ctx@ = pointer to CBC 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 CBC mode, with \
+ * ciphertext stealing and other clever tricks. \
+ * Essentially, data can be encrypted in arbitrary sized \
+ * chunks, although decryption must use the same chunks. \
+ */ \
+ \
+void pre##_cbcencrypt(pre##_cbcctx *ctx, \
+ const void *src, void *dest, \
+ size_t sz) \
+{ \
+ const octet *s = src; \
+ octet *d = dest; \
+ \
+ /* --- Empty blocks are trivial --- */ \
+ \
+ if (!sz) \
+ return; \
+ \
+ /* --- Extra magical case for a short block --- * \
+ * \
+ * Encrypt the IV, then exclusive-or the plaintext with the octets \
+ * of the encrypted IV, shifting ciphertext octets in instead. This \
+ * basically switches over to CFB. \
+ */ \
+ \
+ if (sz < PRE##_BLKSZ) { \
+ octet b[PRE##_BLKSZ]; \
+ unsigned i; \
+ \
+ pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
+ BLKC_STORE(PRE, b, ctx->iv); \
+ for (i = 0; i < sz; i++) \
+ d[i] = b[i] ^ s[i]; \
+ memmove(b, b + sz, PRE##_BLKSZ - sz); \
+ memcpy(b + PRE##_BLKSZ - sz, d, sz); \
+ BLKC_LOAD(PRE, ctx->iv, b); \
+ return; \
+ } \
+ \
+ /* --- Do the main chunk of encryption --- * \
+ * \
+ * This will do the whole lot if it's a whole number of blocks. For \
+ * each block, XOR it with the previous ciphertext in @iv@, encrypt, \
+ * and keep a copy of the ciphertext for the next block. \
+ */ \
+ \
+ while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \
+ BLKC_XLOAD(PRE, ctx->iv, s); \
+ pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
+ BLKC_STORE(PRE, d, ctx->iv); \
+ s += PRE##_BLKSZ; \
+ d += PRE##_BLKSZ; \
+ sz -= PRE##_BLKSZ; \
+ } \
+ \
+ /* --- Do the tail-end block and bit-left-over --- * \
+ * \
+ * This isn't very efficient. That shouldn't matter much. \
+ */ \
+ \
+ if (sz) { \
+ octet b[PRE##_BLKSZ]; \
+ unsigned i; \
+ \
+ /* --- Let @sz@ be the size of the partial block --- */ \
+ \
+ sz -= PRE##_BLKSZ; \
+ \
+ /* --- First stage --- * \
+ * \
+ * XOR the complete block with the current IV, and encrypt it. The \
+ * first part of the result is the partial ciphertext block. Don't \
+ * write that out yet, because I've not read the partial plaintext \
+ * block. \
+ */ \
+ \
+ BLKC_XLOAD(PRE, ctx->iv, s); \
+ pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
+ BLKC_STORE(PRE, b, ctx->iv); \
+ \
+ /* --- Second stage --- * \
+ * \
+ * Now XOR in the partial plaintext block, writing out the \
+ * ciphertext as I go. Then encrypt, and write the complete \
+ * ciphertext block. \
+ */ \
+ \
+ s += PRE##_BLKSZ; \
+ d += PRE##_BLKSZ; \
+ for (i = 0; i < sz; i++) { \
+ register octet x = b[i]; \
+ b[i] ^= s[i]; \
+ d[i] = x; \
+ } \
+ BLKC_LOAD(PRE, ctx->iv, b); \
+ pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
+ BLKC_STORE(PRE, d - PRE##_BLKSZ, ctx->iv); \
+ } \
+ \
+ /* --- Done --- */ \
+ \
+ return; \
+} \
+ \
+/* --- @pre_cbcdecrypt@ --- * \
+ * \
+ * Arguments: @pre_cbcctx *ctx@ = pointer to CBC 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 CBC mode, with \
+ * ciphertext stealing and other clever tricks. \
+ * Essentially, data can be encrypted in arbitrary sized \
+ * chunks, although decryption must use the same chunks. \
+ */ \
+ \
+void pre##_cbcdecrypt(pre##_cbcctx *ctx, \
+ const void *src, void *dest, \
+ size_t sz) \
+{ \
+ const octet *s = src; \
+ octet *d = dest; \
+ \
+ /* --- Empty blocks are trivial --- */ \
+ \
+ if (!sz) \
+ return; \
+ \
+ /* --- Extra magical case for a short block --- * \
+ * \
+ * Encrypt the IV, then exclusive-or the ciphertext with the octets \
+ * of the encrypted IV, shifting ciphertext octets in instead. This \
+ * basically switches over to CFB. \
+ */ \
+ \
+ if (sz < PRE##_BLKSZ) { \
+ octet b[PRE##_BLKSZ], c[PRE##_BLKSZ]; \
+ unsigned i; \
+ \
+ pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv); \
+ BLKC_STORE(PRE, b, ctx->iv); \
+ for (i = 0; i < sz; i++) { \
+ register octet x = s[i]; \
+ d[i] = b[i] ^ x; \
+ c[i] = x; \
+ } \
+ memmove(b, b + sz, PRE##_BLKSZ - sz); \
+ memcpy(b + PRE##_BLKSZ - sz, c, sz); \
+ BLKC_LOAD(PRE, ctx->iv, b); \
+ return; \
+ } \
+ \
+ /* --- Do the main chunk of decryption --- * \
+ * \
+ * This will do the whole lot if it's a whole number of blocks. For \
+ * each block, decrypt, XOR it with the previous ciphertext in @iv@, \
+ * and keep a copy of the ciphertext for the next block. \
+ */ \
+ \
+ while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) { \
+ uint32 b[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \
+ BLKC_LOAD(PRE, niv, s); \
+ pre##_dblk(&ctx->ctx, niv, b); \
+ BLKC_XSTORE(PRE, d, b, ctx->iv); \
+ BLKC_MOVE(PRE, ctx->iv, niv); \
+ s += PRE##_BLKSZ; \
+ d += PRE##_BLKSZ; \
+ sz -= PRE##_BLKSZ; \
+ } \
+ \
+ /* --- Do the tail-end block and bit-left-over --- * \
+ * \
+ * This isn't very efficient. That shouldn't matter much. \
+ */ \
+ \
+ if (sz) { \
+ octet b[PRE##_BLKSZ]; \
+ uint32 bk[PRE##_BLKSZ / 4], niv[PRE##_BLKSZ / 4]; \
+ unsigned i; \
+ \
+ /* --- Let @sz@ be the size of the partial block --- */ \
+ \
+ sz -= PRE##_BLKSZ; \
+ \
+ /* --- First stage --- * \
+ * \
+ * Take the complete ciphertext block, and decrypt it. This block \
+ * is carried over for the next encryption operation. \
+ */ \
+ \
+ BLKC_LOAD(PRE, niv, s); \
+ pre##_dblk(&ctx->ctx, niv, bk); \
+ \
+ /* --- Second stage --- * \
+ * \
+ * XORing the first few bytes of this with the partial ciphertext \
+ * block recovers the partial plaintext block. At the same time, \
+ * write the partial ciphertext block's contents in ready for stage \
+ * three. \
+ */ \
+ \
+ BLKC_STORE(PRE, b, bk); \
+ s += PRE##_BLKSZ; \
+ d += PRE##_BLKSZ; \
+ for (i = 0; i < sz; i++) { \
+ register octet x = s[i]; \
+ d[i] = b[i] ^ x; \
+ b[i] = x; \
+ } \
+ \
+ /* --- Third stage --- * \
+ * \
+ * Decrypt the block we've got left, and XOR with the initial IV to \
+ * recover the complete plaintext block. \
+ */ \
+ \
+ BLKC_LOAD(PRE, bk, b); \
+ pre##_dblk(&ctx->ctx, bk, bk); \
+ BLKC_XSTORE(PRE, d - PRE##_BLKSZ, bk, ctx->iv); \
+ BLKC_MOVE(PRE, ctx->iv, niv); \
+ } \
+ \
+ /* --- Done --- */ \
+ \
+ return; \
+} \
+ \
+/* --- Generic cipher interface --- */ \
+ \
+static const gcipher_ops gops; \
+ \
+typedef struct gctx { \
+ gcipher c; \
+ pre##_cbcctx k; \
+} gctx; \
+ \
+static gcipher *ginit(const void *k, size_t sz) \
+{ \
+ gctx *g = CREATE(gctx); \
+ g->c.ops = &gops; \
+ pre##_cbcinit(&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##_cbcencrypt(&g->k, s, t, sz); \
+} \
+ \
+static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \
+{ \
+ gctx *g = (gctx *)c; \
+ pre##_cbcdecrypt(&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##_cbcsetiv(&g->k, iv); \
+} \
+ \
+static const gcipher_ops gops = { \
+ &pre##_cbc.b, \
+ gencrypt, gdecrypt, gdestroy, gsetiv, 0 \
+}; \
+ \
+const gccipher pre##_cbc = { \
+ { #pre "-cbc", PRE##_KEYSZ, PRE##_BLKSZ }, \
+ ginit \
+}; \
+ \
+CBC_TEST(PRE, pre)
+
+/*----- Test rig ----------------------------------------------------------*/
+
+#ifdef TEST_RIG
+
+#include <stdio.h>
+
+#include "daftstory.h"
+
+/* --- @CBC_TEST@ --- *
+ *
+ * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
+ *
+ * Use: Standard test rig for CBC functions.
+ */
+
+#define CBC_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##_cbcctx ctx; \
+ pre##_ctx k; \
+ int status = 0; \
+ int done = 0; \
+ \
+ size_t keysz = PRE##_KEYSZ ? \
+ PRE##_KEYSZ : strlen((const char *)key); \
+ \
+ fputs(#pre "-cbc: ", stdout); \
+ \
+ pre##_init(&k, key, keysz); \
+ pre##_cbcsetkey(&ctx, &k); \
+ \
+ while (sz <= sizeof(text)) { \
+ rest = sizeof(text) - sz; \
+ memcpy(ct, text, sizeof(text)); \
+ pre##_cbcsetiv(&ctx, iv); \
+ pre##_cbcencrypt(&ctx, ct, ct, sz); \
+ pre##_cbcencrypt(&ctx, ct + sz, ct + sz, rest); \
+ memcpy(pt, ct, sizeof(text)); \
+ pre##_cbcsetiv(&ctx, iv); \
+ pre##_cbcdecrypt(&ctx, pt, pt, sz); \
+ pre##_cbcdecrypt(&ctx, pt + sz, pt + sz, rest); \
+ 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 CBC_TEST(PRE, pre)
+#endif
+
+/*----- That's all, folks -------------------------------------------------*/
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif
projects / u / mdw / catacomb / blobdiff