ct.c, ct.h: New constant-time operations.

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

diff --git a/cbc-def.h b/cbc-def.h
index c0fc600..d14c952 100644 (file)
--- a/cbc-def.h
+++ b/cbc-def.h
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: cbc-def.h,v 1.5 2004/04/08 01:36:15 mdw Exp $
+ * $Id: cbc-def.h,v 1.6 2004/04/17 09:58:36 mdw Exp $
  *
  * Definitions for cipher block chaining mode
  *
  * (c) 1999 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of Catacomb.
  *
@@ -15,12 +15,12 @@
  * 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,
@@ -179,8 +179,10 @@ void pre##_cbcencrypt(pre##_cbcctx *ctx,                           \
                                                                        \
     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];                                              \
+    if (d) {                                                           \
+      for (i = 0; i < sz; i++)                                         \
+       d[i] = b[i] ^ (s ? s[i] : 0);                                   \
+    }                                                                  \
     memmove(b, b + sz, PRE##_BLKSZ - sz);                              \
     memcpy(b + PRE##_BLKSZ - sz, d, sz);                               \
     BLKC_LOAD(PRE, ctx->iv, b);                                                \
@@ -195,11 +197,15 @@ void pre##_cbcencrypt(pre##_cbcctx *ctx,                          \
    */                                                                  \
                                                                        \
   while (sz >= 2 * PRE##_BLKSZ || sz == PRE##_BLKSZ) {                 \
-    BLKC_XLOAD(PRE, ctx->iv, s);                                       \
+    if (s) {                                                           \
+      BLKC_XLOAD(PRE, ctx->iv, s);                                     \
+      s += PRE##_BLKSZ;                                                        \
+    }                                                                  \
     pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv);                           \
-    BLKC_STORE(PRE, d, ctx->iv);                                       \
-    s += PRE##_BLKSZ;                                                  \
-    d += PRE##_BLKSZ;                                                  \
+    if (d) {                                                           \
+      BLKC_STORE(PRE, d, ctx->iv);                                     \
+      d += PRE##_BLKSZ;                                                        \
+    }                                                                  \
     sz -= PRE##_BLKSZ;                                                 \
   }                                                                    \
                                                                        \
@@ -224,7 +230,7 @@ void pre##_cbcencrypt(pre##_cbcctx *ctx,                            \
      * block.                                                          \
      */                                                                        \
                                                                        \
-    BLKC_XLOAD(PRE, ctx->iv, s);                                       \
+    if (s) BLKC_XLOAD(PRE, ctx->iv, s);                                        \
     pre##_eblk(&ctx->ctx, ctx->iv, ctx->iv);                           \
     BLKC_STORE(PRE, b, ctx->iv);                                       \
                                                                        \
@@ -235,16 +241,16 @@ void pre##_cbcencrypt(pre##_cbcctx *ctx,                          \
      * ciphertext block.                                               \
      */                                                                        \
                                                                        \
-    s += PRE##_BLKSZ;                                                  \
-    d += PRE##_BLKSZ;                                                  \
+    if (s) s += PRE##_BLKSZ;                                           \
+    if (d) d += PRE##_BLKSZ;                                           \
     for (i = 0; i < sz; i++) {                                         \
       register octet x = b[i];                                         \
-      b[i] ^= s[i];                                                    \
-      d[i] = x;                                                                \
+      if (s) b[i] ^= s[i];                                             \
+      if (d) 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);                         \
+    if (d) BLKC_STORE(PRE, d - PRE##_BLKSZ, ctx->iv);                  \
   }                                                                    \
                                                                        \
   /* --- Done --- */                                                   \
@@ -502,22 +508,22 @@ int main(void)                                                            \
     if (memcmp(pt, text, sizeof(text)) == 0) {                         \
       done++;                                                          \
       if (sizeof(text) < 40 || done % 8 == 0)                          \
-        fputc('.', stdout);                                            \
+       fputc('.', stdout);                                             \
       if (done % 480 == 0)                                             \
-        fputs("\n\t", stdout);                                         \
+       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(", "); hexdump(text + sz, rest);                         \
+       fputc('\n', stdout);                                            \
       printf("\tciphertext     = "); hexdump(ct, sz);                  \
-        printf(", "); hexdump(ct + sz, rest);                          \
-        fputc('\n', stdout);                                           \
+       printf(", "); hexdump(ct + sz, rest);                           \
+       fputc('\n', stdout);                                            \
       printf("\trecovered text = "); hexdump(pt, sz);                  \
-        printf(", "); hexdump(pt + sz, rest);                          \
-        fputc('\n', stdout);                                           \
+       printf(", "); hexdump(pt + sz, rest);                           \
+       fputc('\n', stdout);                                            \
       fputc('\n', stdout);                                             \
     }                                                                  \
     if (sz < 63)                                                       \