X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/symm/skipjack.c diff --git a/symm/skipjack.c b/symm/skipjack.c new file mode 100644 index 0000000..bd58ede --- /dev/null +++ b/symm/skipjack.c @@ -0,0 +1,176 @@ +/* -*-c-*- + * + * The Skipjack 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 + +#include "blkc.h" +#include "gcipher.h" +#include "skipjack.h" +#include "skipjack-tab.h" + +/*----- Global variables --------------------------------------------------*/ + +const octet skipjack_keysz[] = { KSZ_SET, 10, 0 }; + +/*----- The Skipjack S-box ------------------------------------------------*/ + +static const octet f[256] = SKIPJACK_S; + +/*----- Main code ---------------------------------------------------------*/ + +/* --- @skipjack_init@ --- * + * + * Arguments: @skipjack_ctx *k@ = pointer to key block + * @const void *buf@ = pointer to key buffer + * @size_t sz@ = size of key material + * + * Returns: --- + * + * Use: Initializes a Skipjack key buffer. The key buffer must be + * exactly 10 bytes long. + */ + +void skipjack_init(skipjack_ctx *k, const void *buf, size_t sz) +{ + const octet *b = buf; + uint32 crud; + KSZ_ASSERT(skipjack, sz); + k->ka = LOAD32(b); + k->kb = LOAD32(b + 4); + crud = LOAD16(b + 8); + k->kc = U32((crud << 16) | (k->ka >> 16)); + k->kd = U32((k->ka << 16) | (k->kb >> 16)); + k->ke = U32((k->kb << 16) | crud); + crud = 0; +} + +/* --- @skipjack_eblk@, @skipjack_dblk@ --- * + * + * Arguments: @const skipjack_ctx *k@ = pointer to key block + * @const uint32 s[2]@ = pointer to source block + * @uint32 d[2]@ = pointer to skipjacktination block + * + * Returns: --- + * + * Use: Low-level block encryption and decryption. + */ + +#define G(x, k) do { \ + octet _x = U8(x >> 8), _y = U8(x); \ + _x ^= f[_y ^ U8(k >> 24)]; \ + _y ^= f[_x ^ U8(k >> 16)]; \ + _x ^= f[_y ^ U8(k >> 8)]; \ + _y ^= f[_x ^ U8(k >> 0)]; \ + x = (_x << 8) | _y; \ +} while (0) + +#define RULE_A(w, x, y, z, n, k) do { \ + G(w, k); z ^= w ^ n++; \ +} while (0) + +#define RULE_B(w, x, y, z, n, k) do { \ + x ^= w ^ n++; G(w, k); \ +} while (0) + +void skipjack_eblk(const skipjack_ctx *k, const uint32 *s, uint32 *d) +{ + unsigned n = 1; + uint16 w = U16(s[0] >> 16), x = U16(s[0]); + uint16 y = U16(s[1] >> 16), z = U16(s[1]); + uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke; + + RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb); + RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd); + RULE_A(w, x, y, z, n, ke); RULE_A(z, w, x, y, n, ka); + RULE_A(y, z, w, x, n, kb); RULE_A(x, y, z, w, n, kc); + RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke); + RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb); + RULE_B(w, x, y, z, n, kc); RULE_B(z, w, x, y, n, kd); + RULE_B(y, z, w, x, n, ke); RULE_B(x, y, z, w, n, ka); + RULE_A(w, x, y, z, n, kb); RULE_A(z, w, x, y, n, kc); + RULE_A(y, z, w, x, n, kd); RULE_A(x, y, z, w, n, ke); + RULE_A(w, x, y, z, n, ka); RULE_A(z, w, x, y, n, kb); + RULE_A(y, z, w, x, n, kc); RULE_A(x, y, z, w, n, kd); + RULE_B(w, x, y, z, n, ke); RULE_B(z, w, x, y, n, ka); + RULE_B(y, z, w, x, n, kb); RULE_B(x, y, z, w, n, kc); + RULE_B(w, x, y, z, n, kd); RULE_B(z, w, x, y, n, ke); + RULE_B(y, z, w, x, n, ka); RULE_B(x, y, z, w, n, kb); + + d[0] = ((uint32)w << 16) | (uint32)x; + d[1] = ((uint32)y << 16) | (uint32)z; +} + +#define G_INV(x, k) do { \ + octet _x = U8(x >> 8), _y = U8(x); \ + _y ^= f[_x ^ U8(k >> 0)]; \ + _x ^= f[_y ^ U8(k >> 8)]; \ + _y ^= f[_x ^ U8(k >> 16)]; \ + _x ^= f[_y ^ U8(k >> 24)]; \ + x = (_x << 8) | _y; \ +} while (0) + +#define RULE_A_INV(w, x, y, z, n, i) do { \ + w ^= x ^ --n; G_INV(x, i); \ +} while (0) + +#define RULE_B_INV(w, x, y, z, n, i) do { \ + G_INV(x, i); y ^= x ^ --n; \ +} while (0) + +void skipjack_dblk(const skipjack_ctx *k, const uint32 *s, uint32 *d) +{ + unsigned n = 33; + uint16 w = U16(s[0] >> 16), x = U16(s[0]); + uint16 y = U16(s[1] >> 16), z = U16(s[1]); + uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd, ke = k->ke; + + RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka); + RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd); + RULE_B_INV(w, x, y, z, n, kc); RULE_B_INV(x, y, z, w, n, kb); + RULE_B_INV(y, z, w, x, n, ka); RULE_B_INV(z, w, x, y, n, ke); + RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc); + RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka); + RULE_A_INV(w, x, y, z, n, ke); RULE_A_INV(x, y, z, w, n, kd); + RULE_A_INV(y, z, w, x, n, kc); RULE_A_INV(z, w, x, y, n, kb); + RULE_B_INV(w, x, y, z, n, ka); RULE_B_INV(x, y, z, w, n, ke); + RULE_B_INV(y, z, w, x, n, kd); RULE_B_INV(z, w, x, y, n, kc); + RULE_B_INV(w, x, y, z, n, kb); RULE_B_INV(x, y, z, w, n, ka); + RULE_B_INV(y, z, w, x, n, ke); RULE_B_INV(z, w, x, y, n, kd); + RULE_A_INV(w, x, y, z, n, kc); RULE_A_INV(x, y, z, w, n, kb); + RULE_A_INV(y, z, w, x, n, ka); RULE_A_INV(z, w, x, y, n, ke); + RULE_A_INV(w, x, y, z, n, kd); RULE_A_INV(x, y, z, w, n, kc); + RULE_A_INV(y, z, w, x, n, kb); RULE_A_INV(z, w, x, y, n, ka); + + d[0] = ((uint32)w << 16) | (uint32)x; + d[1] = ((uint32)y << 16) | (uint32)z; +} + +BLKC_TEST(SKIPJACK, skipjack) + +/*----- That's all, folks -------------------------------------------------*/