X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/83c017f3fb115a67734e94dca02095b62cae5e80..8dd8c294e9f330eb6b975c2b96cf9bbfcd087e5e:/serpent.c?ds=sidebyside diff --git a/serpent.c b/serpent.c new file mode 100644 index 0000000..d04d65b --- /dev/null +++ b/serpent.c @@ -0,0 +1,223 @@ +/* -*-c-*- + * + * $Id: serpent.c,v 1.1 2000/06/17 12:08:43 mdw Exp $ + * + * The Serpent 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: serpent.c,v $ + * Revision 1.1 2000/06/17 12:08:43 mdw + * New cipher. + * + */ + +/*----- Header files ------------------------------------------------------*/ + +#include +#include + +#include + +#include "blkc.h" +#include "gcipher.h" +#include "serpent.h" +#include "serpent-sbox.h" + +/*----- Global variables --------------------------------------------------*/ + +const octet serpent_keysz[] = { KSZ_RANGE, SERPENT_KEYSZ, 0, 32, 1 }; + +/*----- Main code ---------------------------------------------------------*/ + +/* --- @serpent_init@ --- * + * + * Arguments: @serpent_ctx *k@ = pointer to context block to initialize + * @const void *buf@ = pointer to input buffer + * @size_t sz@ = size of input buffer + * + * Returns: --- + * + * Use: Initializes a Serpent context. The key may be any length of + * up to 32 bytes (256 bits). + */ + +void serpent_init(serpent_ctx *k, const void *buf, size_t sz) +{ + uint32 a; + unsigned b; + const octet *p, *q; + size_t i; + uint32 pk[8 + 132]; + + KSZ_ASSERT(serpent, sz); + + /* --- Read the key into the buffer --- */ + + if (sz > 32) + sz = 32; + i = 0; p = buf; q = p + sz; + a = 0; b = 0; + while (p < q) { + a |= (uint32)*p++ << b; + b += 8; + if (b == 32) { + pk[i++] = a; + a = 0; b = 0; + } + } + + /* --- Pad short keys --- */ + + if (i < 8) { + a |= 0x01 << b; + b += 8; + pk[i++] = a; + for (; i < 8; i++) + pk[i] = 0; + } + + /* --- Expand the prekeys to fill the buffer --- */ + + for (i = 8; i < 8 + 132; i++) { + uint32 x = (pk[i - 8] ^ pk[i - 5] ^ pk[i - 3] ^ pk[i - 1] ^ + (i - 8) ^ 0x9e3779b9); + k->k[i - 8] = pk[i] = ROL32(x, 11); + } + + /* --- Now substitute everything --- */ + + i = 0; + goto midway; + while (i < 132) { +#define KSUB(r) do { \ + uint32 a, b, c, d; \ + a = k->k[i]; b = k->k[i + 1]; c = k->k[i + 2]; d = k->k[i + 3]; \ + S##r(a, b, c, d); \ + k->k[i] = a; k->k[i + 1] = b; k->k[i + 2] = c; k->k[i + 3] = d; \ + i += 4; \ +} while (0) + KSUB(2); KSUB(1); KSUB(0); KSUB(7); + KSUB(6); KSUB(5); KSUB(4); + midway: + KSUB(3); +#undef KSUB + } +} + +/* --- @serpent_eblk@, @serpent_dblk@ --- * + * + * Arguments: @const serpent_ctx *k@ = pointer to key context + * @const uint32 s[4]@ = pointer to source block + * @uint32 d[4]@ = pointer to destination block + * + * Returns: --- + * + * Use: Low-level block encryption. + */ + +#define EROUND(a, b, c, d, r, k) do { \ + a ^= *k++; b ^= *k++; c ^= *k++; d ^= *k++; \ + S##r(a, b, c, d); \ + a = ROL32(a, 13); c = ROL32(c, 3); b ^= a ^ c; d ^= c ^ (a << 3); \ + b = ROL32(b, 1); d = ROL32(d, 7); a ^= b ^ d; c ^= d ^ (b << 7); \ + a = ROL32(a, 5); c = ROL32(c, 22); \ +} while (0) + +#define DROUND(a, b, c, d, r, k) do { \ + IS##r(a, b, c, d); \ + d ^= *--k; c ^= *--k; b ^= *--k; a ^= *--k; \ + a = ROR32(a, 5); c = ROR32(c, 22); a ^= b ^ d; c ^= d ^ (b << 7); \ + b = ROR32(b, 1); d = ROR32(d, 7); b ^= a ^ c; d ^= c ^ (a << 3); \ + a = ROR32(a, 13); c = ROR32(c, 3); \ +} while (0) + +void serpent_eblk(const serpent_ctx *k, const uint32 *s, uint32 *d) +{ + uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; + const uint32 *kk = k->k; + + EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); + EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); + EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); + EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); + + EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); + EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); + EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); + EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); + + EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); + EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); + EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); + EROUND(aa, bb, cc, dd, 6, kk); EROUND(aa, bb, cc, dd, 7, kk); + + EROUND(aa, bb, cc, dd, 0, kk); EROUND(aa, bb, cc, dd, 1, kk); + EROUND(aa, bb, cc, dd, 2, kk); EROUND(aa, bb, cc, dd, 3, kk); + EROUND(aa, bb, cc, dd, 4, kk); EROUND(aa, bb, cc, dd, 5, kk); + EROUND(aa, bb, cc, dd, 6, kk); + + aa ^= *kk++; bb ^= *kk++; cc ^= *kk++; dd ^= *kk++; + S7(aa, bb, cc, dd); + aa ^= *kk++; bb ^= *kk++; cc ^= *kk++; dd ^= *kk++; + d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; +} + +void serpent_dblk(const serpent_ctx *k, const uint32 *s, uint32 *d) +{ + uint32 aa = s[0], bb = s[1], cc = s[2], dd = s[3]; + const uint32 *kk = k->k + 132; + + dd ^= *--kk; cc ^= *--kk; bb ^= *--kk; aa ^= *--kk; + + DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); + DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); + DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); + DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); + + DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); + DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); + DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); + DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); + + DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); + DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); + DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); + DROUND(aa, bb, cc, dd, 1, kk); DROUND(aa, bb, cc, dd, 0, kk); + + DROUND(aa, bb, cc, dd, 7, kk); DROUND(aa, bb, cc, dd, 6, kk); + DROUND(aa, bb, cc, dd, 5, kk); DROUND(aa, bb, cc, dd, 4, kk); + DROUND(aa, bb, cc, dd, 3, kk); DROUND(aa, bb, cc, dd, 2, kk); + DROUND(aa, bb, cc, dd, 1, kk); + + IS0(aa, bb, cc, dd); + dd ^= *--kk; cc ^= *--kk; bb ^= *--kk; aa ^= *--kk; + d[0] = aa; d[1] = bb; d[2] = cc; d[3] = dd; +} + +BLKC_TEST(SERPENT, serpent) + +/*----- That's all, folks -------------------------------------------------*/