X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/399da52417e00da756f53cc882dd072d81a9e984..9810d7498bccbb8b9316e6af7a99a3621bed45eb:/cast128.c diff --git a/cast128.c b/cast128.c new file mode 100644 index 0000000..b985da2 --- /dev/null +++ b/cast128.c @@ -0,0 +1,310 @@ +/* -*-c-*- + * + * $Id: cast128.c,v 1.1 2000/06/17 10:49:14 mdw Exp $ + * + * The CAST-128 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. + */ + +/*----- Revision history --------------------------------------------------* + * + * $Log: cast128.c,v $ + * Revision 1.1 2000/06/17 10:49:14 mdw + * New cipher. + * + */ + +/*----- Header files ------------------------------------------------------*/ + +#include +#include +#include +#include + +#include + +#include "blkc.h" +#include "cast-base.h" +#include "cast128.h" +#include "gcipher.h" +#include "paranoia.h" + +/*----- Global variables --------------------------------------------------*/ + +const octet cast128_keysz[] = { KSZ_RANGE, CAST128_KEYSZ, 0, 16, 1 }; + +/*----- Main code ---------------------------------------------------------*/ + +/* --- @cast128_init@ --- * + * + * Arguments: @cast128_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 CAST-128 key buffer. CAST-128 accepts + * 128-bit keys or shorter. + */ + +void cast128_init(cast128_ctx *k, const void *buf, size_t sz) +{ + const octet *p = buf; + uint32 kk[4]; + unsigned i; + uint32 a, b, c, d, aa, bb, cc, dd; + + /* --- Fiddle with the key size a bit --- */ + + KSZ_ASSERT(cast128, sz); + + if (sz > 10) + k->r = 16; + else + k->r = 12; + + /* --- Read the key into the array --- */ + + i = 0; + b = 32; aa = 0; + for (;;) { + if (!sz) + break; + b -= 8; + aa |= ((uint32)*p++ << b); + sz--; + if (b == 0) { + kk[i++] = aa; + if (i == 4) + break; + aa = 0; + b = 32; + } + } + + for (; i < 4; i++) { + kk[i] = aa; + aa = 0; + } + + /* --- Read the key words out --- */ + + a = kk[0]; b = kk[1]; c = kk[2]; d = kk[3]; + +#define X_0123 a +#define X_4567 b +#define X_89ab c +#define X_cdef d + +#define X_0 U8(X_0123 >> 24) +#define X_1 U8(X_0123 >> 16) +#define X_2 U8(X_0123 >> 8) +#define X_3 U8(X_0123 >> 0) +#define X_4 U8(X_4567 >> 24) +#define X_5 U8(X_4567 >> 16) +#define X_6 U8(X_4567 >> 8) +#define X_7 U8(X_4567 >> 0) +#define X_8 U8(X_89ab >> 24) +#define X_9 U8(X_89ab >> 16) +#define X_a U8(X_89ab >> 8) +#define X_b U8(X_89ab >> 0) +#define X_c U8(X_cdef >> 24) +#define X_d U8(X_cdef >> 16) +#define X_e U8(X_cdef >> 8) +#define X_f U8(X_cdef >> 0) + +#define Z_0123 aa +#define Z_4567 bb +#define Z_89ab cc +#define Z_cdef dd + +#define Z_0 U8(Z_0123 >> 24) +#define Z_1 U8(Z_0123 >> 16) +#define Z_2 U8(Z_0123 >> 8) +#define Z_3 U8(Z_0123 >> 0) +#define Z_4 U8(Z_4567 >> 24) +#define Z_5 U8(Z_4567 >> 16) +#define Z_6 U8(Z_4567 >> 8) +#define Z_7 U8(Z_4567 >> 0) +#define Z_8 U8(Z_89ab >> 24) +#define Z_9 U8(Z_89ab >> 16) +#define Z_a U8(Z_89ab >> 8) +#define Z_b U8(Z_89ab >> 0) +#define Z_c U8(Z_cdef >> 24) +#define Z_d U8(Z_cdef >> 16) +#define Z_e U8(Z_cdef >> 8) +#define Z_f U8(Z_cdef >> 0) + +#define SK(w, x, y, z) \ + cast_sk[0][w] ^ cast_sk[1][x] ^ cast_sk[2][y] ^ cast_sk[3][z] + + i = 0; + Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; + Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; + Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; + Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; + k->km[i++] = SK(Z_8, Z_9, Z_7, Z_6) ^ cast_sk[0][Z_2]; + k->km[i++] = SK(Z_a, Z_b, Z_5, Z_4) ^ cast_sk[1][Z_6]; + k->km[i++] = SK(Z_c, Z_d, Z_3, Z_2) ^ cast_sk[2][Z_9]; + k->km[i++] = SK(Z_e, Z_f, Z_1, Z_0) ^ cast_sk[3][Z_c]; + X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; + X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; + X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; + X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; + k->km[i++] = SK(X_3, X_2, X_c, X_d) ^ cast_sk[0][X_8]; + k->km[i++] = SK(X_1, X_0, X_e, X_f) ^ cast_sk[1][X_d]; + k->km[i++] = SK(X_7, X_6, X_8, X_9) ^ cast_sk[2][X_3]; + k->km[i++] = SK(X_5, X_4, X_a, X_b) ^ cast_sk[3][X_7]; + Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; + Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; + Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; + Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; + k->km[i++] = SK(Z_3, Z_2, Z_c, Z_d) ^ cast_sk[0][Z_9]; + k->km[i++] = SK(Z_1, Z_0, Z_e, Z_f) ^ cast_sk[1][Z_c]; + k->km[i++] = SK(Z_7, Z_6, Z_8, Z_9) ^ cast_sk[2][Z_2]; + k->km[i++] = SK(Z_5, Z_4, Z_a, Z_b) ^ cast_sk[3][Z_6]; + X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; + X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; + X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; + X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; + k->km[i++] = SK(X_8, X_9, X_7, X_6) ^ cast_sk[0][X_3]; + k->km[i++] = SK(X_a, X_b, X_5, X_4) ^ cast_sk[1][X_7]; + k->km[i++] = SK(X_c, X_d, X_3, X_2) ^ cast_sk[2][X_8]; + k->km[i++] = SK(X_e, X_f, X_1, X_0) ^ cast_sk[3][X_d]; + + i = 0; + Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; + Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; + Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; + Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; + k->kr[i++] = (SK(Z_8, Z_9, Z_7, Z_6) ^ cast_sk[0][Z_2]) & 0x1f; + k->kr[i++] = (SK(Z_a, Z_b, Z_5, Z_4) ^ cast_sk[1][Z_6]) & 0x1f; + k->kr[i++] = (SK(Z_c, Z_d, Z_3, Z_2) ^ cast_sk[2][Z_9]) & 0x1f; + k->kr[i++] = (SK(Z_e, Z_f, Z_1, Z_0) ^ cast_sk[3][Z_c]) & 0x1f; + X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; + X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; + X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; + X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; + k->kr[i++] = (SK(X_3, X_2, X_c, X_d) ^ cast_sk[0][X_8]) & 0x1f; + k->kr[i++] = (SK(X_1, X_0, X_e, X_f) ^ cast_sk[1][X_d]) & 0x1f; + k->kr[i++] = (SK(X_7, X_6, X_8, X_9) ^ cast_sk[2][X_3]) & 0x1f; + k->kr[i++] = (SK(X_5, X_4, X_a, X_b) ^ cast_sk[3][X_7]) & 0x1f; + Z_0123 = X_0123 ^ SK(X_d, X_f, X_c, X_e) ^ cast_sk[2][X_8]; + Z_4567 = X_89ab ^ SK(Z_0, Z_2, Z_1, Z_3) ^ cast_sk[3][X_a]; + Z_89ab = X_cdef ^ SK(Z_7, Z_6, Z_5, Z_4) ^ cast_sk[0][X_9]; + Z_cdef = X_4567 ^ SK(Z_a, Z_9, Z_b, Z_8) ^ cast_sk[1][X_b]; + k->kr[i++] = (SK(Z_3, Z_2, Z_c, Z_d) ^ cast_sk[0][Z_9]) & 0x1f; + k->kr[i++] = (SK(Z_1, Z_0, Z_e, Z_f) ^ cast_sk[1][Z_c]) & 0x1f; + k->kr[i++] = (SK(Z_7, Z_6, Z_8, Z_9) ^ cast_sk[2][Z_2]) & 0x1f; + k->kr[i++] = (SK(Z_5, Z_4, Z_a, Z_b) ^ cast_sk[3][Z_6]) & 0x1f; + X_0123 = Z_89ab ^ SK(Z_5, Z_7, Z_4, Z_6) ^ cast_sk[2][Z_0]; + X_4567 = Z_0123 ^ SK(X_0, X_2, X_1, X_3) ^ cast_sk[3][Z_2]; + X_89ab = Z_4567 ^ SK(X_7, X_6, X_5, X_4) ^ cast_sk[0][Z_1]; + X_cdef = Z_cdef ^ SK(X_a, X_9, X_b, X_8) ^ cast_sk[1][Z_3]; + k->kr[i++] = (SK(X_8, X_9, X_7, X_6) ^ cast_sk[0][X_3]) & 0x1f; + k->kr[i++] = (SK(X_a, X_b, X_5, X_4) ^ cast_sk[1][X_7]) & 0x1f; + k->kr[i++] = (SK(X_c, X_d, X_3, X_2) ^ cast_sk[2][X_8]) & 0x1f; + k->kr[i++] = (SK(X_e, X_f, X_1, X_0) ^ cast_sk[3][X_d]) & 0x1f; + + BURN(kk); +} + +/* --- @cast128_eblk@, @cast128_dblk@ --- * + * + * Arguments: @const cast128_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 cast128_eblk(const cast128_ctx *k, const uint32 *s, uint32 *d) +{ + uint32 a = s[0], b = s[1]; + const uint32 *km = k->km; + const octet *kr = k->kr; + + switch (k->r) { + default: + CAST_R1(*km++, *kr++, a, b); + CAST_R2(*km++, *kr++, b, a); + CAST_R3(*km++, *kr++, a, b); + CAST_R1(*km++, *kr++, b, a); + CAST_R2(*km++, *kr++, a, b); + CAST_R3(*km++, *kr++, b, a); + CAST_R1(*km++, *kr++, a, b); + CAST_R2(*km++, *kr++, b, a); + CAST_R3(*km++, *kr++, a, b); + CAST_R1(*km++, *kr++, b, a); + CAST_R2(*km++, *kr++, a, b); + CAST_R3(*km++, *kr++, b, a); + if (k->r == 12) + break; + CAST_R1(*km++, *kr++, a, b); + CAST_R2(*km++, *kr++, b, a); + CAST_R3(*km++, *kr++, a, b); + CAST_R1(*km++, *kr++, b, a); + break; + } + + d[0] = b; d[1] = a; +} + +void cast128_dblk(const cast128_ctx *k, const uint32 *s, uint32 *d) +{ + uint32 a = s[0], b = s[1]; + const uint32 *km = k->km + k->r; + const octet *kr = k->kr + k->r; + + switch (k->r) { + case 16: + default: + CAST_R1(*--km, *--kr, a, b); + CAST_R3(*--km, *--kr, b, a); + CAST_R2(*--km, *--kr, a, b); + CAST_R1(*--km, *--kr, b, a); + case 12: + CAST_R3(*--km, *--kr, a, b); + CAST_R2(*--km, *--kr, b, a); + CAST_R1(*--km, *--kr, a, b); + CAST_R3(*--km, *--kr, b, a); + CAST_R2(*--km, *--kr, a, b); + CAST_R1(*--km, *--kr, b, a); + CAST_R3(*--km, *--kr, a, b); + CAST_R2(*--km, *--kr, b, a); + CAST_R1(*--km, *--kr, a, b); + CAST_R3(*--km, *--kr, b, a); + CAST_R2(*--km, *--kr, a, b); + CAST_R1(*--km, *--kr, b, a); + break; + } + + d[0] = b; d[1] = a; +} + +BLKC_TEST(CAST128, cast128) + +/*----- That's all, folks -------------------------------------------------*/