Initial twofish support

Rev: src/symmetric/generate_q.c:1.1
Rev: src/symmetric/include/twofish.h:1.1
Rev: src/symmetric/twofish.c:1.1

generate_q.c

+/*
+ * generate_q - Generates the permutations q0 and q1 for twofish.
+ * Copyright (C) 1999 Ruud de Rooij <ruud@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <stdio.h>
+
+typedef unsigned char byte;
+
+#define ror4(x) (((x) >> 1) | (((x) & 1) << 3))
+
+static byte q0(byte x)
+{
+
+    static byte t0[16] = { 0x8, 0x1, 0x7, 0xD, 0x6, 0xF, 0x3, 0x2,
+                           0x0, 0xB, 0x5, 0x9, 0xE, 0xC, 0xA, 0x4 };
+    static byte t1[16] = { 0xE, 0xC, 0xB, 0x8, 0x1, 0x2, 0x3, 0x5,
+                           0xF, 0x4, 0xA, 0x6, 0x7, 0x0, 0x9, 0xD };
+    static byte t2[16] = { 0xB, 0xA, 0x5, 0xE, 0x6, 0xD, 0x9, 0x0,
+                           0xC, 0x8, 0xF, 0x3, 0x2, 0x4, 0x7, 0x1 };
+    static byte t3[16] = { 0xD, 0x7, 0xF, 0x4, 0x1, 0x2, 0x6, 0xE,
+                           0x9, 0xB, 0x3, 0x0, 0x8, 0x5, 0xC, 0xA };
+
+    byte a0 = x / 16;
+    byte b0 = x % 16;
+
+    byte a1 = a0 ^ b0;
+    byte b1 = a0 ^ ror4(b0) ^ ((8*a0) % 16);
+
+    byte a2 = t0[a1];
+    byte b2 = t1[b1];
+
+    byte a3 = a2 ^ b2;
+    byte b3 = a2 ^ ror4(b2) ^ ((8*a2) % 16);
+
+    byte a4 = t2[a3];
+    byte b4 = t3[b3];
+
+    byte y = 16*b4 + a4;
+
+    return y;
+}
+
+static byte q1(byte x)
+{
+    static byte t0[16] = { 0x2, 0x8, 0xB, 0xD, 0xF, 0x7, 0x6, 0xE,
+                           0x3, 0x1, 0x9, 0x4, 0x0, 0xA, 0xC, 0x5 };
+    static byte t1[16] = { 0x1, 0xE, 0x2, 0xB, 0x4, 0xC, 0x3, 0x7,
+                           0x6, 0xD, 0xA, 0x5, 0xF, 0x9, 0x0, 0x8 };
+    static byte t2[16] = { 0x4, 0xC, 0x7, 0x5, 0x1, 0x6, 0x9, 0xA,
+                           0x0, 0xE, 0xD, 0x8, 0x2, 0xB, 0x3, 0xF };
+    static byte t3[16] = { 0xB, 0x9, 0x5, 0x1, 0xC, 0x3, 0xD, 0xE,
+                           0x6, 0x4, 0x7, 0xF, 0x2, 0x0, 0x8, 0xA };
+
+    byte a0 = x / 16;
+    byte b0 = x % 16;
+
+    byte a1 = a0 ^ b0;
+    byte b1 = a0 ^ ror4(b0) ^ ((8*a0) % 16);
+
+    byte a2 = t0[a1];
+    byte b2 = t1[b1];
+
+    byte a3 = a2 ^ b2;
+    byte b3 = a2 ^ ror4(b2) ^ ((8*a2) % 16);
+
+    byte a4 = t2[a3];
+    byte b4 = t3[b3];
+
+    byte y = 16*b4 + a4;
+
+    return y;
+}
+
+int
+main(void)
+{
+    int i, j;
+
+    printf("static byte q0[] = { ");
+    for (i = 0; i < 32; i++) {
+        for (j = 0; j < 8; j++)
+            printf("0x%02X, ", q0(i*8+j));
+        if (i == 31)
+            printf("};\n\n");
+        else
+            printf("\n                     ");
+    }
+
+    printf("static byte q1[] = { ");
+    for (i = 0; i < 32; i++) {
+        for (j = 0; j < 8; j++)
+            printf("0x%02X, ", q1(i*8+j));
+        if (i == 31)
+            printf("};\n");
+        else
+            printf("\n                     ");
+    }
+
+    return 0;
+}

include/twofish.h

+/*
+ * twofish - An implementation of the twofish cipher.
+ * Copyright (C) 1999 Ruud de Rooij <ruud@debian.org>
+ *
+ * Modifications for lsh
+ * Copyright (C) 1999 J.H.M. Dassen (Ray) <jdassen@wi.LeidenUniv.nl>
+ *
+ * This library 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.
+ *
+ * This library 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 this library; if not, write to the Free
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+/*
+ * Twofish is a 128-bit block cipher that accepts a variable-length
+ * key up to 256 bits, designed by Bruce Schneier and others.  See
+ * http://www.counterpane.com/twofish.html for details.
+ */
+
+#if !defined(TWOFISH_H)
+#define TWOFISH_H
+
+#include <stdlib.h>	/* For size_t */
+
+#include "crypto_types.h"
+
+#define TWOFISH_BLOCKSIZE 16 /* bytes */
+
+
+/* Other key lengths are possible, but in the context of the ssh protocols,
+ * 256 bits is the default. */
+#define TWOFISH_KEYSIZE 32 /* bytes */
+
+/* Allow keys of size 128 <= bits <= 256 */
+
+#define TWOFISH_MIN_KEYSIZE 16 /* bytes */
+#define TWOFISH_MAX_KEYSIZE 32 /* bytes */
+
+typedef struct {
+    UINT32 keys[40];
+    UINT32 s_box[4][256];
+} TWOFISH_context;
+
+/* TWOFISH_context * twofish_setup(size_t keysize, const void * key);
+ *
+ * Set up internal tables required for twofish encryption and decryption.
+ *
+ * The key size is specified in bytes.  Key sizes up to 32 bytes are
+ * supported.  Larger key sizes are silently truncated.  The function
+ * returns a pointer which must be passed as the first argument to
+ * twofish_encrypt() and twofish_decrypt().  When no more encryption or
+ * decryption with this key is to be performed, the storage for the tables
+ * can be reclaimed with the free() function.
+ * If no memory is available to store the tables, twofish_setup()
+ * returns NULL.
+ */
+
+TWOFISH_context * twofish_setup(size_t keysize, const void *key);
+
+/* void twofish_encrypt(void * context,
+ *                      const void * plaintext,
+ *                      void * ciphertext);
+ *
+ * Encrypt 16 bytes of data with the twofish algorithm.
+ *
+ * Before this function can be used, twofish_setup() must be used in order to
+ * set up various tables required for the encryption algorithm.
+ * The first argument is the handle returned from twofish_setup().
+ * This function always encrypts 16 bytes of plaintext to 16 bytes of
+ * ciphertext.  The memory areas of the plaintext and the ciphertext can
+ * overlap.
+ */
+
+void twofish_encrypt(void *context, const void *plaintext, void *ciphertext);
+
+/* void twofish_decrypt(void * context,
+ *                      const void * ciphertext,
+ *                      void * plaintext);
+ *
+ * Decrypt 16 bytes of data with the twofish algorithm.
+ *
+ * Before this function can be used, twofish_setup() must be used in order to
+ * set up various tables required for the decryption algorithm.
+ * The first argument is the handle returned from twofish_setup().
+ * This function always decrypts 16 bytes of ciphertext to 16 bytes of
+ * plaintext.  The memory areas of the plaintext and the ciphertext can
+ * overlap.
+ */
+
+void twofish_decrypt(void *context, const void *ciphertext, void *plaintext);
+
+#endif