/* -*-c-*-
*
- * $Id: twofish.c,v 1.1 2000/06/17 12:10:17 mdw Exp $
+ * $Id: twofish.c,v 1.3 2002/01/13 13:37:59 mdw Exp $
*
* Implementation of the Twofish cipher
*
/*----- Revision history --------------------------------------------------*
*
* $Log: twofish.c,v $
+ * Revision 1.3 2002/01/13 13:37:59 mdw
+ * Add support for Twofish family keys.
+ *
+ * Revision 1.2 2000/06/22 18:58:00 mdw
+ * Twofish can handle keys with any byte-aligned size.
+ *
* Revision 1.1 2000/06/17 12:10:17 mdw
* New cipher.
*
/*----- 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 --------------------------------------------------*/
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
/* --- 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 --- */
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++;
}
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 --- */
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 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 --- */