Gather up another utility.

[u/mdw/catacomb] / twofish.c

diff --git a/twofish.c b/twofish.c
index 437a191..e70ad12 100644 (file)
--- a/twofish.c
+++ b/twofish.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: twofish.c,v 1.1 2000/06/17 12:10:17 mdw Exp $
+ * $Id: twofish.c,v 1.5 2004/04/08 01:36:15 mdw Exp $
  *
  * Implementation of the Twofish cipher
  *
@@ -27,14 +27,6 @@
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------* 
- *
- * $Log: twofish.c,v $
- * Revision 1.1  2000/06/17 12:10:17  mdw
- * New cipher.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <assert.h>
@@ -49,7 +41,7 @@
 
 /*----- Global variables --------------------------------------------------*/
 
-const octet twofish_keysz[] = { KSZ_RANGE, TWOFISH_KEYSZ, 4, 32, 4 };
+const octet twofish_keysz[] = { KSZ_RANGE, TWOFISH_KEYSZ, 0, 32, 1 };
 
 /*----- Important tables --------------------------------------------------*/
 
@@ -99,19 +91,22 @@ static uint32 h(uint32 x, const uint32 *l, unsigned k)
          qmds[2][U8(x >> 16)] ^ qmds[3][U8(x >> 24)]);
 }
 
-/* --- @twofish_init@ --- *
+/* --- @twofish_initfk@ --- *
  *
  * Arguments:  @twofish_ctx *k@ = pointer to key block to fill in
  *             @const void *buf@ = pointer to buffer of key material
  *             @size_t sz@ = size of key material
+ *             @const twofish_fk *fk@ = family-key information
  *
  * Returns:    ---
  *
- * Use:                Initializes a Twofish key buffer.  Twofish accepts key sizes
- *             of up to 256 bits (32 bytes).
+ * Use:                Does the underlying Twofish key initialization with family
+ *             key.  Pass in a family-key structure initialized to
+ *             all-bits-zero for a standard key schedule.
  */
 
-void twofish_init(twofish_ctx *k, const void *buf, size_t sz)
+void twofish_initfk(twofish_ctx *k, const void *buf, size_t sz,
+                   const twofish_fk *fk)
 {
 # define KMAX 4
 
@@ -167,8 +162,8 @@ void twofish_init(twofish_ctx *k, const void *buf, size_t sz)
 
       /* --- Extract the easy subkeys --- */
 
-      me[i] = LOAD32_L(q);
-      mo[i] = LOAD32_L(q + 4);
+      me[i] = LOAD32_L(q) ^ fk->t0[2 * i];
+      mo[i] = LOAD32_L(q + 4) ^ fk->t0[2 * i + 1];
 
       /* --- Now do the Reed-Solomon thing --- */
 
@@ -178,8 +173,8 @@ void twofish_init(twofish_ctx *k, const void *buf, size_t sz)
        int k;
 
        for (k = 0; k < 8; k++) {
-         if (*qq)
-           a ^= rsexp[rslog[*qq] + *r];
+         unsigned char x = *qq ^ fk->t1[i * 8 + k];
+         if (x) a ^= rsexp[rslog[x] + *r];
          qq++;
          r++;
        }
@@ -212,6 +207,13 @@ void twofish_init(twofish_ctx *k, const void *buf, size_t sz)
       k->k[i + 1] = ROL32(b, 9);
       ip += 2 * p;
     }
+
+    for (i = 0; i < 8; i++)
+      k->k[i] ^= fk->t23[i];
+    for (i = 8; i < 40; i += 2) {
+      k->k[i] ^= fk->t4[0];
+      k->k[i + 1] ^= fk->t4[1];
+    }
   }
 
   /* --- Construct the S-box tables --- */
@@ -256,6 +258,64 @@ void twofish_init(twofish_ctx *k, const void *buf, size_t sz)
   BURN(s);
 }
 
+/* --- @twofish_init@ --- *
+ *
+ * Arguments:  @twofish_ctx *k@ = pointer to key block to fill in
+ *             @const void *buf@ = pointer to buffer of key material
+ *             @size_t sz@ = size of key material
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes a Twofish key buffer.  Twofish accepts key sizes
+ *             of up to 256 bits (32 bytes).
+ */
+
+void twofish_init(twofish_ctx *k, const void *buf, size_t sz)
+{
+  static const twofish_fk fk = { { 0 } };
+  twofish_initfk(k, buf, sz, &fk);
+}
+
+/* --- @twofish_fkinit@ --- *
+ *
+ * Arguments:  @twofish_fk *fk@ = pointer to family key block
+ *             @const void *buf@ = pointer to buffer of key material
+ *             @size_t sz@ = size of key material
+ *
+ * Returns:    ---
+ *
+ * Use:                Initializes a family-key buffer.  This implementation allows
+ *             family keys of any size acceptable to the Twofish algorithm.
+ */
+
+void twofish_fkinit(twofish_fk *fk, const void *buf, size_t sz)
+{
+  twofish_ctx k;
+  uint32 pt[4], ct[4];
+  const octet *kk;
+  unsigned i;
+
+  twofish_init(&k, buf, sz);
+
+  for (i = 0; i < 4; i++) pt[i] = (uint32)-1;
+  twofish_eblk(&k, pt, fk->t0 + 4);
+
+  kk = buf; sz /= 4;
+  for (i = 0; i < sz; i++) { fk->t0[i] = LOAD32_L(kk); kk += 4; }
+
+  for (i = 0; i < 4; i++) pt[i] = 0; twofish_eblk(&k, pt, ct);
+  for (i = 0; i < 4; i++) STORE32_L(fk->t1 + i * 4, ct[i]);
+  pt[0] = 1; twofish_eblk(&k, pt, ct);
+  for (i = 0; i < 4; i++) STORE32_L(fk->t1 + 4 + i * 4, ct[i]);
+
+  pt[0] = 2; twofish_eblk(&k, pt, fk->t23 + 0);
+  pt[0] = 3; twofish_eblk(&k, pt, fk->t23 + 4);
+  pt[0] = 4; twofish_eblk(&k, pt, ct);
+  fk->t4[0] = ct[0]; fk->t4[1] = ct[1];
+
+  BURN(k);
+}
+
 /*----- Main encryption ---------------------------------------------------*/
 
 /* --- Feistel function --- */