452 строки
11 KiB
C
452 строки
11 KiB
C
/*
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* Cryptographic API.
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*
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* AES Cipher Algorithm.
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*
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* Based on Brian Gladman's code.
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*
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* Linux developers:
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* Alexander Kjeldaas <astor@fast.no>
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* Herbert Valerio Riedel <hvr@hvrlab.org>
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* Kyle McMartin <kyle@debian.org>
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* Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API).
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* ---------------------------------------------------------------------------
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* Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
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* All rights reserved.
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*
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* LICENSE TERMS
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*
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* The free distribution and use of this software in both source and binary
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* form is allowed (with or without changes) provided that:
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*
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* 1. distributions of this source code include the above copyright
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* notice, this list of conditions and the following disclaimer;
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*
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* 2. distributions in binary form include the above copyright
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* notice, this list of conditions and the following disclaimer
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* in the documentation and/or other associated materials;
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*
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* 3. the copyright holder's name is not used to endorse products
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* built using this software without specific written permission.
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*
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* ALTERNATIVELY, provided that this notice is retained in full, this product
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* may be distributed under the terms of the GNU General Public License (GPL),
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* in which case the provisions of the GPL apply INSTEAD OF those given above.
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*
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* DISCLAIMER
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*
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* This software is provided 'as is' with no explicit or implied warranties
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* in respect of its properties, including, but not limited to, correctness
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* and/or fitness for purpose.
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* ---------------------------------------------------------------------------
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*/
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/* Some changes from the Gladman version:
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s/RIJNDAEL(e_key)/E_KEY/g
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s/RIJNDAEL(d_key)/D_KEY/g
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/crypto.h>
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#include <asm/byteorder.h>
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#define AES_MIN_KEY_SIZE 16
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#define AES_MAX_KEY_SIZE 32
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#define AES_BLOCK_SIZE 16
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/*
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* #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
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*/
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inline static u8
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byte(const u32 x, const unsigned n)
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{
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return x >> (n << 3);
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}
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#define u32_in(x) le32_to_cpu(*(const u32 *)(x))
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#define u32_out(to, from) (*(u32 *)(to) = cpu_to_le32(from))
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struct aes_ctx {
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int key_length;
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u32 E[60];
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u32 D[60];
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};
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#define E_KEY ctx->E
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#define D_KEY ctx->D
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static u8 pow_tab[256] __initdata;
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static u8 log_tab[256] __initdata;
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static u8 sbx_tab[256] __initdata;
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static u8 isb_tab[256] __initdata;
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static u32 rco_tab[10];
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static u32 ft_tab[4][256];
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static u32 it_tab[4][256];
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static u32 fl_tab[4][256];
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static u32 il_tab[4][256];
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static inline u8 __init
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f_mult (u8 a, u8 b)
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{
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u8 aa = log_tab[a], cc = aa + log_tab[b];
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return pow_tab[cc + (cc < aa ? 1 : 0)];
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}
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#define ff_mult(a,b) (a && b ? f_mult(a, b) : 0)
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#define f_rn(bo, bi, n, k) \
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bo[n] = ft_tab[0][byte(bi[n],0)] ^ \
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ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
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ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
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ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
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#define i_rn(bo, bi, n, k) \
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bo[n] = it_tab[0][byte(bi[n],0)] ^ \
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it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
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it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
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it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
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#define ls_box(x) \
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( fl_tab[0][byte(x, 0)] ^ \
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fl_tab[1][byte(x, 1)] ^ \
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fl_tab[2][byte(x, 2)] ^ \
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fl_tab[3][byte(x, 3)] )
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#define f_rl(bo, bi, n, k) \
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bo[n] = fl_tab[0][byte(bi[n],0)] ^ \
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fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
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fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
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fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
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#define i_rl(bo, bi, n, k) \
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bo[n] = il_tab[0][byte(bi[n],0)] ^ \
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il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
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il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
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il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
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static void __init
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gen_tabs (void)
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{
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u32 i, t;
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u8 p, q;
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/* log and power tables for GF(2**8) finite field with
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0x011b as modular polynomial - the simplest primitive
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root is 0x03, used here to generate the tables */
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for (i = 0, p = 1; i < 256; ++i) {
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pow_tab[i] = (u8) p;
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log_tab[p] = (u8) i;
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p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
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}
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log_tab[1] = 0;
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for (i = 0, p = 1; i < 10; ++i) {
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rco_tab[i] = p;
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p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
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}
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for (i = 0; i < 256; ++i) {
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p = (i ? pow_tab[255 - log_tab[i]] : 0);
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q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
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p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
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sbx_tab[i] = p;
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isb_tab[p] = (u8) i;
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}
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for (i = 0; i < 256; ++i) {
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p = sbx_tab[i];
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t = p;
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fl_tab[0][i] = t;
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fl_tab[1][i] = rol32(t, 8);
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fl_tab[2][i] = rol32(t, 16);
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fl_tab[3][i] = rol32(t, 24);
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t = ((u32) ff_mult (2, p)) |
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((u32) p << 8) |
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((u32) p << 16) | ((u32) ff_mult (3, p) << 24);
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ft_tab[0][i] = t;
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ft_tab[1][i] = rol32(t, 8);
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ft_tab[2][i] = rol32(t, 16);
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ft_tab[3][i] = rol32(t, 24);
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p = isb_tab[i];
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t = p;
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il_tab[0][i] = t;
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il_tab[1][i] = rol32(t, 8);
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il_tab[2][i] = rol32(t, 16);
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il_tab[3][i] = rol32(t, 24);
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t = ((u32) ff_mult (14, p)) |
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((u32) ff_mult (9, p) << 8) |
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((u32) ff_mult (13, p) << 16) |
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((u32) ff_mult (11, p) << 24);
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it_tab[0][i] = t;
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it_tab[1][i] = rol32(t, 8);
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it_tab[2][i] = rol32(t, 16);
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it_tab[3][i] = rol32(t, 24);
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}
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}
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#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
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#define imix_col(y,x) \
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u = star_x(x); \
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v = star_x(u); \
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w = star_x(v); \
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t = w ^ (x); \
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(y) = u ^ v ^ w; \
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(y) ^= ror32(u ^ t, 8) ^ \
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ror32(v ^ t, 16) ^ \
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ror32(t,24)
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/* initialise the key schedule from the user supplied key */
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#define loop4(i) \
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{ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
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t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \
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t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \
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t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \
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t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \
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}
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#define loop6(i) \
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{ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \
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t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \
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t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \
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t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \
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t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \
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t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \
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t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \
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}
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#define loop8(i) \
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{ t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \
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t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \
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t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \
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t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \
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t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \
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t = E_KEY[8 * i + 4] ^ ls_box(t); \
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E_KEY[8 * i + 12] = t; \
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t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \
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t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \
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t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \
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}
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static int
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aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags)
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{
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struct aes_ctx *ctx = ctx_arg;
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u32 i, t, u, v, w;
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if (key_len != 16 && key_len != 24 && key_len != 32) {
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*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
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return -EINVAL;
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}
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ctx->key_length = key_len;
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E_KEY[0] = u32_in (in_key);
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E_KEY[1] = u32_in (in_key + 4);
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E_KEY[2] = u32_in (in_key + 8);
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E_KEY[3] = u32_in (in_key + 12);
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switch (key_len) {
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case 16:
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t = E_KEY[3];
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for (i = 0; i < 10; ++i)
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loop4 (i);
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break;
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case 24:
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E_KEY[4] = u32_in (in_key + 16);
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t = E_KEY[5] = u32_in (in_key + 20);
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for (i = 0; i < 8; ++i)
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loop6 (i);
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break;
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case 32:
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E_KEY[4] = u32_in (in_key + 16);
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E_KEY[5] = u32_in (in_key + 20);
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E_KEY[6] = u32_in (in_key + 24);
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t = E_KEY[7] = u32_in (in_key + 28);
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for (i = 0; i < 7; ++i)
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loop8 (i);
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break;
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}
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D_KEY[0] = E_KEY[0];
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D_KEY[1] = E_KEY[1];
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D_KEY[2] = E_KEY[2];
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D_KEY[3] = E_KEY[3];
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for (i = 4; i < key_len + 24; ++i) {
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imix_col (D_KEY[i], E_KEY[i]);
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}
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return 0;
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}
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/* encrypt a block of text */
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#define f_nround(bo, bi, k) \
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f_rn(bo, bi, 0, k); \
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f_rn(bo, bi, 1, k); \
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f_rn(bo, bi, 2, k); \
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f_rn(bo, bi, 3, k); \
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k += 4
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#define f_lround(bo, bi, k) \
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f_rl(bo, bi, 0, k); \
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f_rl(bo, bi, 1, k); \
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f_rl(bo, bi, 2, k); \
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f_rl(bo, bi, 3, k)
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static void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in)
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{
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const struct aes_ctx *ctx = ctx_arg;
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u32 b0[4], b1[4];
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const u32 *kp = E_KEY + 4;
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b0[0] = u32_in (in) ^ E_KEY[0];
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b0[1] = u32_in (in + 4) ^ E_KEY[1];
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b0[2] = u32_in (in + 8) ^ E_KEY[2];
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b0[3] = u32_in (in + 12) ^ E_KEY[3];
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if (ctx->key_length > 24) {
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f_nround (b1, b0, kp);
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f_nround (b0, b1, kp);
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}
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if (ctx->key_length > 16) {
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f_nround (b1, b0, kp);
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f_nround (b0, b1, kp);
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}
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f_nround (b1, b0, kp);
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f_nround (b0, b1, kp);
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f_nround (b1, b0, kp);
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f_nround (b0, b1, kp);
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f_nround (b1, b0, kp);
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f_nround (b0, b1, kp);
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f_nround (b1, b0, kp);
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f_nround (b0, b1, kp);
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f_nround (b1, b0, kp);
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f_lround (b0, b1, kp);
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u32_out (out, b0[0]);
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u32_out (out + 4, b0[1]);
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u32_out (out + 8, b0[2]);
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u32_out (out + 12, b0[3]);
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}
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/* decrypt a block of text */
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#define i_nround(bo, bi, k) \
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i_rn(bo, bi, 0, k); \
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i_rn(bo, bi, 1, k); \
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i_rn(bo, bi, 2, k); \
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i_rn(bo, bi, 3, k); \
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k -= 4
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#define i_lround(bo, bi, k) \
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i_rl(bo, bi, 0, k); \
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i_rl(bo, bi, 1, k); \
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i_rl(bo, bi, 2, k); \
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i_rl(bo, bi, 3, k)
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static void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in)
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{
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const struct aes_ctx *ctx = ctx_arg;
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u32 b0[4], b1[4];
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const int key_len = ctx->key_length;
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const u32 *kp = D_KEY + key_len + 20;
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b0[0] = u32_in (in) ^ E_KEY[key_len + 24];
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b0[1] = u32_in (in + 4) ^ E_KEY[key_len + 25];
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b0[2] = u32_in (in + 8) ^ E_KEY[key_len + 26];
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b0[3] = u32_in (in + 12) ^ E_KEY[key_len + 27];
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if (key_len > 24) {
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i_nround (b1, b0, kp);
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i_nround (b0, b1, kp);
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}
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if (key_len > 16) {
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i_nround (b1, b0, kp);
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i_nround (b0, b1, kp);
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}
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i_nround (b1, b0, kp);
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i_nround (b0, b1, kp);
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i_nround (b1, b0, kp);
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i_nround (b0, b1, kp);
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i_nround (b1, b0, kp);
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i_nround (b0, b1, kp);
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i_nround (b1, b0, kp);
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i_nround (b0, b1, kp);
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i_nround (b1, b0, kp);
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i_lround (b0, b1, kp);
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u32_out (out, b0[0]);
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u32_out (out + 4, b0[1]);
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u32_out (out + 8, b0[2]);
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u32_out (out + 12, b0[3]);
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}
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static struct crypto_alg aes_alg = {
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.cra_name = "aes",
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.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
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.cra_blocksize = AES_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct aes_ctx),
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.cra_module = THIS_MODULE,
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.cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
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.cra_u = {
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.cipher = {
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.cia_min_keysize = AES_MIN_KEY_SIZE,
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.cia_max_keysize = AES_MAX_KEY_SIZE,
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.cia_setkey = aes_set_key,
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.cia_encrypt = aes_encrypt,
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.cia_decrypt = aes_decrypt
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}
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}
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};
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static int __init aes_init(void)
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{
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gen_tabs();
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return crypto_register_alg(&aes_alg);
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}
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static void __exit aes_fini(void)
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{
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crypto_unregister_alg(&aes_alg);
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}
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module_init(aes_init);
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module_exit(aes_fini);
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MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
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MODULE_LICENSE("Dual BSD/GPL");
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