diff --git a/des3.c b/des3.c new file mode 100644 index 0000000000000000000000000000000000000000..85186c336b90d8e7202da43d9e0fb94cc8ffe620 --- /dev/null +++ b/des3.c @@ -0,0 +1,72 @@ +/* des3.h + * + * Triple DES cipher. Three key encrypt-decrypt-encrypt. + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2001 Niels M�ller + * + * The nettle library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The nettle library 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 Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +#include "des.h" + +/* It's possible to make some more general pipe construction, like the + * lsh/src/cascade.c, but as in practice it's never used for anything + * like triple DES, it's not worth the effort. */ + +/* On success, returns 1 and sets ctx->status to DES_OK (zero). On + * error, returns 0 and sets ctx->status accordingly. */ +int +des3_set_key(struct des3_ctx *ctx, const uint8_t *key) +{ + unsigned i; + for (i = 0; i<3; i++, key += DES_KEY_SIZE) + if (!des_set_key(&ctx->des[i], key)) + { + ctx->status = ctx->des[i].status; + return 0; + } + ctx->status = DES_OK; + return 1; +} + +void +des3_encrypt(struct des3_ctx *ctx, + unsigned length, uint8_t *dst, + const uint8_t *src) +{ + des_encrypt(&ctx->des[0], + length, dst, src); + des_decrypt(&ctx->des[1], + length, dst, dst); + des_encrypt(&ctx->des[2], + length, dst, dst); +} + +void +des3_decrypt(struct des3_ctx *ctx, + unsigned length, uint8_t *dst, + const uint8_t *src) +{ + des_decrypt(&ctx->des[2], + length, dst, src); + des_encrypt(&ctx->des[1], + length, dst, dst); + des_decrypt(&ctx->des[0], + length, dst, dst); +}