--- /dev/null
+/* -*-c-*-
+ *
+ * The RC2 block cipher
+ *
+ * (c) 2000 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 <mLib/bits.h>
+
+#include "blkc.h"
+#include "gcipher.h"
+#include "paranoia.h"
+#include "rc2.h"
+#include "rc2-tab.h"
+
+/*----- Global variables --------------------------------------------------*/
+
+const octet rc2_keysz[] = { KSZ_RANGE, RC2_KEYSZ, 1, 128, 1 };
+
+/*----- Important tables --------------------------------------------------*/
+
+static const octet pi[256] = RC2_PI;
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @rc2_braindamage@ --- *
+ *
+ * Arguments: @rc2_ctx *k@ = pointer to context to initialize
+ * @const void *buf@ = pointer to key material
+ * @size_t sz@ = size of key material in bytes
+ * @unsigned eb@ = desired effective key size, in bits
+ *
+ * Returns: ---
+ *
+ * Use: Initializes an RC2 expanded key, and braindamages it to the
+ * requested effective key size. This is here for compatibility
+ * reasons. You should be using @rc2_init@ in normal code,
+ * which doesn't actually apply braindamage.
+ */
+
+void rc2_braindamage(rc2_ctx *k, const void *buf, size_t sz, unsigned eb)
+{
+ unsigned t8;
+ uint16 tm;
+ unsigned i;
+ uint16 *kk;
+ octet l[128];
+
+ KSZ_ASSERT(rc2, sz);
+
+ /* --- Compute the braindamage parameters --- */
+
+ t8 = (eb + 7) / 8;
+ tm = 0xff & ((1 << (8 + eb - 8 * t8)) - 1);
+
+ /* --- Copy and expand the initial key --- */
+
+ if (sz > sizeof(l))
+ sz = sizeof(l);
+ memcpy(l, buf, sz);
+
+ for (i = sz; i < sizeof(l); i++)
+ l[i] = pi[U8(l[i - 1] + l[i - sz])];
+
+ /* --- Braindamage the key --- */
+
+ i = sizeof(l) - t8;
+ l[i] = pi[l[i] & tm];
+ while (i) {
+ i--;
+ l[i] = pi[U8(l[i + 1] ^ l[i + t8])];
+ }
+
+ /* --- Write it to the key block --- */
+
+ kk = k->k;
+ for (i = 0; i < sizeof(l); i += 2)
+ *kk++ = LOAD16_L(l + i);
+ BURN(l);
+}
+
+/* --- @rc2_init@ --- *
+ *
+ * Arguments: @rc2_ctx *k@ = pointer to context to initialize
+ * @const void *buf@ = pointer to key material
+ * @size_t sz@ = size of key material in bytes
+ *
+ * Returns: ---
+ *
+ * Use: Initializes an RC2 expanded key. The effective key size is
+ * set to be equal to the real key size, in bits.
+ */
+
+void rc2_init(rc2_ctx *k, const void *buf, size_t sz)
+{
+ rc2_braindamage(k, buf, sz, sz * 8);
+}
+
+/*----- Encryption and decryption -----------------------------------------*/
+
+#define MIX(a, b, c, d, r, kk) do { \
+ a += *kk++ + (d & c) + (~d & b); \
+ a = ROL16(a, r); \
+} while (0)
+
+#define MASH(a, d, k) do { \
+ a += k[d & 63]; \
+} while (0)
+
+#define UNMIX(a, b, c, d, r, kk) do { \
+ a = ROR16(a, r); \
+ a -= *--kk + (d & c) + (~d & b); \
+} while (0)
+
+#define UNMASH(a, d, k) do { \
+ a -= k[d & 63]; \
+} while (0)
+
+/* --- @rc2_eblk@, @rc2_dblk@ --- *
+ *
+ * Arguments: @const rc2_ctx *k@ = pointer to RC2 context
+ * @const uint32 s[2]@ = pointer to source block
+ * @const uint32 d[2]@ = pointer to destination block
+ *
+ * Returns: ---
+ *
+ * Use: Low-level block encryption and decryption.
+ */
+
+void rc2_eblk(const rc2_ctx *k, const uint32 *s, uint32 *dst)
+{
+ uint16 a = U16(s[0] >> 0), b = U16(s[0] >> 16);
+ uint16 c = U16(s[1] >> 0), d = U16(s[1] >> 16);
+ const uint16 *kk = k->k;
+
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MASH(a, d, k->k); MASH(b, a, k->k);
+ MASH(c, b, k->k); MASH(d, c, k->k);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MASH(a, d, k->k); MASH(b, a, k->k);
+ MASH(c, b, k->k); MASH(d, c, k->k);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+ MIX(a, b, c, d, 1, kk); MIX(b, c, d, a, 2, kk);
+ MIX(c, d, a, b, 3, kk); MIX(d, a, b, c, 5, kk);
+
+ dst[0] = a | (b << 16); dst[1] = c | (d << 16);
+}
+
+void rc2_dblk(const rc2_ctx *k, const uint32 *s, uint32 *dst)
+{
+ uint16 a = U16(s[0] >> 0), b = U16(s[0] >> 16);
+ uint16 c = U16(s[1] >> 0), d = U16(s[1] >> 16);
+ const uint16 *kk = k->k + 64;
+
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMASH(d, c, k->k); UNMASH(c, b, k->k);
+ UNMASH(b, a, k->k); UNMASH(a, d, k->k);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMASH(d, c, k->k); UNMASH(c, b, k->k);
+ UNMASH(b, a, k->k); UNMASH(a, d, k->k);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+ UNMIX(d, a, b, c, 5, kk); UNMIX(c, d, a, b, 3, kk);
+ UNMIX(b, c, d, a, 2, kk); UNMIX(a, b, c, d, 1, kk);
+
+ dst[0] = a | (b << 16); dst[1] = c | (d << 16);
+}
+
+/*----- Custom test rig ---------------------------------------------------*
+ *
+ * I need to test the braindamage feature.
+ */
+
+#ifdef TEST_RIG
+
+#include <mLib/quis.h>
+#include <mLib/testrig.h>
+
+static int verify(dstr *v)
+{
+ rc2_ctx k;
+ uint32 p[RC2_BLKSZ / 4];
+ uint32 c[RC2_BLKSZ / 4];
+ uint32 d[RC2_BLKSZ / 4];
+ dstr b = DSTR_INIT;
+ unsigned bd = *(unsigned *)v[1].buf;
+ int ok = 1;
+
+ /* --- Initialize the key buffer --- */
+
+ dstr_ensure(&b, RC2_BLKSZ);
+ b.len = RC2_BLKSZ;
+ rc2_braindamage(&k, v[0].buf, v[0].len, bd);
+ BLKC_LOAD(RC2, p, v[2].buf);
+ BLKC_LOAD(RC2, c, v[3].buf);
+
+ /* --- Test encryption --- */
+
+ BLKC_MOVE(RC2, d, p);
+ rc2_eblk(&k, d, d);
+ BLKC_STORE(RC2, b.buf, d);
+ if (memcmp(b.buf, v[3].buf, RC2_BLKSZ)) {
+ ok = 0;
+ printf("\nfail encryption:"
+ "\n\tkey = ");
+ type_hex.dump(&v[0], stdout);
+ printf("\n\tbraindamage= %u", bd);
+ printf("\n\tplaintext = "); type_hex.dump(&v[2], stdout);
+ printf("\n\texpected = "); type_hex.dump(&v[3], stdout);
+ printf("\n\tcalculated = "); type_hex.dump(&b, stdout);
+ putchar('\n');
+ }
+
+ /* --- Test decryption --- */
+
+ BLKC_MOVE(RC2, d, c);
+ rc2_dblk(&k, d, d);
+ BLKC_STORE(RC2, b.buf, d);
+ if (memcmp(b.buf, v[2].buf, RC2_BLKSZ)) {
+ ok = 0;
+ printf("\nfail decryption:"
+ "\n\tkey = ");
+ type_hex.dump(&v[0], stdout);
+ printf("\n\tbraindamage= %u", bd);
+ printf("\n\tciphertext = "); type_hex.dump(&v[3], stdout);
+ printf("\n\texpected = "); type_hex.dump(&v[2], stdout);
+ printf("\n\tcalculated = "); type_hex.dump(&b, stdout);
+ putchar('\n');
+ }
+
+ /* --- Return --- */
+
+ return (ok);
+}
+
+static test_chunk defs[] = {
+ { "rc2", verify, { &type_hex, &type_int, &type_hex, &type_hex, 0 } },
+ { 0, 0, { 0 } }
+};
+
+int main(int argc, char *argv[])
+{
+ test_run(argc, argv, defs, SRCDIR"/t/rc2");
+ return (0);
+}
+
+#endif
+
+/*----- That's all, folks -------------------------------------------------*/
projects / u / mdw / catacomb / blobdiff