X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/6134d9683efd0dd88740a4a7f4804bbb2d92e912..3a65506d4df316377c9b838ef5954b5d856215ee:/rc2.c diff --git a/rc2.c b/rc2.c new file mode 100644 index 0000000..9ced44c --- /dev/null +++ b/rc2.c @@ -0,0 +1,369 @@ +/* -*-c-*- + * + * $Id: rc2.c,v 1.1 2000/06/17 11:54:34 mdw Exp $ + * + * 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. + */ + +/*----- Revision history --------------------------------------------------* + * + * $Log: rc2.c,v $ + * Revision 1.1 2000/06/17 11:54:34 mdw + * New cipher. + * + */ + +/*----- Header files ------------------------------------------------------*/ + +#include +#include + +#include + +#include "blkc.h" +#include "gcipher.h" +#include "paranoia.h" +#include "rc2.h" + +/*----- Global variables --------------------------------------------------*/ + +const octet rc2_keysz[] = { KSZ_RANGE, RC2_KEYSZ, 1, 128, 1 }; + +/*----- Important tables --------------------------------------------------*/ + +static const octet pi[] = { + 0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, + 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d, + 0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, + 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2, + 0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, + 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32, + 0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, + 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82, + 0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, + 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc, + 0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, + 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26, + 0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, + 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03, + 0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, + 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7, + 0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, + 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a, + 0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, + 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec, + 0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, + 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39, + 0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, + 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31, + 0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, + 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9, + 0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, + 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9, + 0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, + 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e, + 0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, + 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad +}; + +/*----- 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 +#include + +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"/tests/rc2"); + return (0); +} + +#endif + +/*----- That's all, folks -------------------------------------------------*/