LXR linux/crypto/blowfish

   1/*
   2 * Cryptographic API.
   3 *
   4 * Blowfish Cipher Algorithm, by Bruce Schneier.
   5 * http://www.counterpane.com/blowfish.html
   6 *
   7 * Adapted from Kerneli implementation.
   8 *
   9 * Copyright (c) Herbert Valerio Riedel <hvr@hvrlab.org>
  10 * Copyright (c) Kyle McMartin <kyle@debian.org>
  11 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  12 *
  13 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2 of the License, or
  16 * (at your option) any later version.
  17 *
  18 */
  19#include <linux/init.h>
  20#include <linux/module.h>
  21#include <linux/mm.h>
  22#include <asm/byteorder.h>
  23#include <linux/crypto.h>
  24#include <linux/types.h>
  25#include <crypto/blowfish.h>
  26
  27/*
  28 * Round loop unrolling macros, S is a pointer to a S-Box array
  29 * organized in 4 unsigned longs at a row.
  30 */
  31#define GET32_3(x) (((x) & 0xff))
  32#define GET32_2(x) (((x) >> (8)) & (0xff))
  33#define GET32_1(x) (((x) >> (16)) & (0xff))
  34#define GET32_0(x) (((x) >> (24)) & (0xff))
  35
  36#define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \
  37                S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])
  38
  39#define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })
  40
  41static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  42{
  43        struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
  44        const __be32 *in_blk = (const __be32 *)src;
  45        __be32 *const out_blk = (__be32 *)dst;
  46        const u32 *P = ctx->p;
  47        const u32 *S = ctx->s;
  48        u32 yl = be32_to_cpu(in_blk[0]);
  49        u32 yr = be32_to_cpu(in_blk[1]);
  50
  51        ROUND(yr, yl, 0);
  52        ROUND(yl, yr, 1);
  53        ROUND(yr, yl, 2);
  54        ROUND(yl, yr, 3);
  55        ROUND(yr, yl, 4);
  56        ROUND(yl, yr, 5);
  57        ROUND(yr, yl, 6);
  58        ROUND(yl, yr, 7);
  59        ROUND(yr, yl, 8);
  60        ROUND(yl, yr, 9);
  61        ROUND(yr, yl, 10);
  62        ROUND(yl, yr, 11);
  63        ROUND(yr, yl, 12);
  64        ROUND(yl, yr, 13);
  65        ROUND(yr, yl, 14);
  66        ROUND(yl, yr, 15);
  67
  68        yl ^= P[16];
  69        yr ^= P[17];
  70
  71        out_blk[0] = cpu_to_be32(yr);
  72        out_blk[1] = cpu_to_be32(yl);
  73}
  74
  75static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  76{
  77        struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
  78        const __be32 *in_blk = (const __be32 *)src;
  79        __be32 *const out_blk = (__be32 *)dst;
  80        const u32 *P = ctx->p;
  81        const u32 *S = ctx->s;
  82        u32 yl = be32_to_cpu(in_blk[0]);
  83        u32 yr = be32_to_cpu(in_blk[1]);
  84
  85        ROUND(yr, yl, 17);
  86        ROUND(yl, yr, 16);
  87        ROUND(yr, yl, 15);
  88        ROUND(yl, yr, 14);
  89        ROUND(yr, yl, 13);
  90        ROUND(yl, yr, 12);
  91        ROUND(yr, yl, 11);
  92        ROUND(yl, yr, 10);
  93        ROUND(yr, yl, 9);
  94        ROUND(yl, yr, 8);
  95        ROUND(yr, yl, 7);
  96        ROUND(yl, yr, 6);
  97        ROUND(yr, yl, 5);
  98        ROUND(yl, yr, 4);
  99        ROUND(yr, yl, 3);
 100        ROUND(yl, yr, 2);
 101
 102        yl ^= P[1];
 103        yr ^= P[0];
 104
 105        out_blk[0] = cpu_to_be32(yr);
 106        out_blk[1] = cpu_to_be32(yl);
 107}
 108
 109static struct crypto_alg alg = {
 110        .cra_name               =       "blowfish",
 111        .cra_driver_name        =       "blowfish-generic",
 112        .cra_priority           =       100,
 113        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 114        .cra_blocksize          =       BF_BLOCK_SIZE,
 115        .cra_ctxsize            =       sizeof(struct bf_ctx),
 116        .cra_alignmask          =       3,
 117        .cra_module             =       THIS_MODULE,
 118        .cra_u                  =       { .cipher = {
 119        .cia_min_keysize        =       BF_MIN_KEY_SIZE,
 120        .cia_max_keysize        =       BF_MAX_KEY_SIZE,
 121        .cia_setkey             =       blowfish_setkey,
 122        .cia_encrypt            =       bf_encrypt,
 123        .cia_decrypt            =       bf_decrypt } }
 124};
 125
 126static int __init blowfish_mod_init(void)
 127{
 128        return crypto_register_alg(&alg);
 129}
 130
 131static void __exit blowfish_mod_fini(void)
 132{
 133        crypto_unregister_alg(&alg);
 134}
 135
 136module_init(blowfish_mod_init);
 137module_exit(blowfish_mod_fini);
 138
 139MODULE_LICENSE("GPL");
 140MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
 141MODULE_ALIAS_CRYPTO("blowfish");
 142MODULE_ALIAS_CRYPTO("blowfish-generic");
 143