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blowfish_generic.c
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blowfish_generic.c
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/*
* Cryptographic API.
*
* Blowfish Cipher Algorithm, by Bruce Schneier.
* http://www.counterpane.com/blowfish.html
*
* Adapted from Kerneli implementation.
*
* Copyright (c) Herbert Valerio Riedel <[email protected]>
* Copyright (c) Kyle McMartin <[email protected]>
* Copyright (c) 2002 James Morris <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <asm/byteorder.h>
#include <linux/crypto.h>
#include <linux/types.h>
#include <crypto/blowfish.h>
/*
* Round loop unrolling macros, S is a pointer to a S-Box array
* organized in 4 unsigned longs at a row.
*/
#define GET32_3(x) (((x) & 0xff))
#define GET32_2(x) (((x) >> (8)) & (0xff))
#define GET32_1(x) (((x) >> (16)) & (0xff))
#define GET32_0(x) (((x) >> (24)) & (0xff))
#define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \
S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])
#define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })
static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
const __be32 *in_blk = (const __be32 *)src;
__be32 *const out_blk = (__be32 *)dst;
const u32 *P = ctx->p;
const u32 *S = ctx->s;
u32 yl = be32_to_cpu(in_blk[0]);
u32 yr = be32_to_cpu(in_blk[1]);
ROUND(yr, yl, 0);
ROUND(yl, yr, 1);
ROUND(yr, yl, 2);
ROUND(yl, yr, 3);
ROUND(yr, yl, 4);
ROUND(yl, yr, 5);
ROUND(yr, yl, 6);
ROUND(yl, yr, 7);
ROUND(yr, yl, 8);
ROUND(yl, yr, 9);
ROUND(yr, yl, 10);
ROUND(yl, yr, 11);
ROUND(yr, yl, 12);
ROUND(yl, yr, 13);
ROUND(yr, yl, 14);
ROUND(yl, yr, 15);
yl ^= P[16];
yr ^= P[17];
out_blk[0] = cpu_to_be32(yr);
out_blk[1] = cpu_to_be32(yl);
}
static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
{
struct bf_ctx *ctx = crypto_tfm_ctx(tfm);
const __be32 *in_blk = (const __be32 *)src;
__be32 *const out_blk = (__be32 *)dst;
const u32 *P = ctx->p;
const u32 *S = ctx->s;
u32 yl = be32_to_cpu(in_blk[0]);
u32 yr = be32_to_cpu(in_blk[1]);
ROUND(yr, yl, 17);
ROUND(yl, yr, 16);
ROUND(yr, yl, 15);
ROUND(yl, yr, 14);
ROUND(yr, yl, 13);
ROUND(yl, yr, 12);
ROUND(yr, yl, 11);
ROUND(yl, yr, 10);
ROUND(yr, yl, 9);
ROUND(yl, yr, 8);
ROUND(yr, yl, 7);
ROUND(yl, yr, 6);
ROUND(yr, yl, 5);
ROUND(yl, yr, 4);
ROUND(yr, yl, 3);
ROUND(yl, yr, 2);
yl ^= P[1];
yr ^= P[0];
out_blk[0] = cpu_to_be32(yr);
out_blk[1] = cpu_to_be32(yl);
}
static struct crypto_alg alg = {
.cra_name = "blowfish",
.cra_driver_name = "blowfish-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = BF_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct bf_ctx),
.cra_alignmask = 3,
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(alg.cra_list),
.cra_u = { .cipher = {
.cia_min_keysize = BF_MIN_KEY_SIZE,
.cia_max_keysize = BF_MAX_KEY_SIZE,
.cia_setkey = blowfish_setkey,
.cia_encrypt = bf_encrypt,
.cia_decrypt = bf_decrypt } }
};
static int __init blowfish_mod_init(void)
{
return crypto_register_alg(&alg);
}
static void __exit blowfish_mod_fini(void)
{
crypto_unregister_alg(&alg);
}
module_init(blowfish_mod_init);
module_exit(blowfish_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Blowfish Cipher Algorithm");
MODULE_ALIAS("blowfish");