X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/symm/des3.c

diff --git a/symm/des3.c b/symm/des3.c
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+/* -*-c-*-
+ *
+ * Implementation of double- and triple-DES
+ *
+ * (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.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <mLib/bits.h>
+
+#include "blkc.h"
+#include "des-base.h"
+#include "des.h"
+#include "des3.h"
+#include "gcipher.h"
+
+/*----- Global variables --------------------------------------------------*/
+
+const octet des3_keysz[] = { KSZ_SET, 21, 7, 8, 14, 16, 24, 0 };
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @des3_init@ --- *
+ *
+ * Arguments:	@des3_ctx *k@ = pointer to key block
+ *		@const void *buf@ = pointer to key buffer
+ *		@size_t sz@ = size of key material
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes a DES key buffer.  The key buffer may have length
+ *		7, 8, 14, 16, 21, or 24.  These correspond to one, two or
+ *		three DES keys, either packed or unpacked (i.e., still
+ *		containing parity bits).
+ */
+
+void des3_init(des3_ctx *k, const void *buf, size_t sz)
+{
+  size_t step;
+  const octet *p = buf;
+
+  KSZ_ASSERT(des3, sz);
+
+  if (sz % 7 == 0)
+    step = 7;
+  else
+    step = 8;
+
+  des_init(&k->a, p, step);
+  if (sz > 8) p += step;
+  des_init(&k->b, p, step);
+  if (sz > 16) p += step; else p = buf;
+  des_init(&k->c, p, step);
+}
+
+/* --- @des3_eblk@, @des3_dblk@ --- *
+ *
+ * Arguments:	@const des3_ctx *k@ = pointer to key block
+ *		@const uint32 s[2]@ = pointer to source block
+ *		@uint32 d[2]@ = pointer to destination block
+ *
+ * Returns:	---
+ *
+ * Use:		Low-level block encryption and decryption.
+ */
+
+void des3_eblk(const des3_ctx *k, const uint32 *s, uint32 *d)
+{
+  uint32 x = s[0], y = s[1];
+  DES_IP(x, y);
+  DES_EBLK(k->a.k, x, y, x, y);
+  DES_DBLK(k->b.k, x, y, x, y);
+  DES_EBLK(k->c.k, x, y, x, y);
+  DES_IPINV(x, y);
+  d[0] = x, d[1] = y;
+}
+
+void des3_dblk(const des3_ctx *k, const uint32 *s, uint32 *d)
+{
+  uint32 x = s[0], y = s[1];
+  DES_IP(x, y);
+  DES_DBLK(k->c.k, x, y, x, y);
+  DES_EBLK(k->b.k, x, y, x, y);
+  DES_DBLK(k->a.k, x, y, x, y);
+  DES_IPINV(x, y);
+  d[0] = x, d[1] = y;
+}
+
+BLKC_TEST(DES3, des3)
+
+/*----- That's all, folks -------------------------------------------------*/