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Add AES support
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1882 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Mark Spencer
232
aestab.c
Executable file
232
aestab.c
Executable file
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/*
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---------------------------------------------------------------------------
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Copyright (c) 2003, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
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All rights reserved.
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LICENSE TERMS
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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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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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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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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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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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DISCLAIMER
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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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Issue Date: 26/08/2003
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*/
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#if defined(__cplusplus)
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extern "C"
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{
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#endif
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#define DO_TABLES
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#include "aesopt.h"
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#if defined(FIXED_TABLES)
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/* implemented in case of wrong call for fixed tables */
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void gen_tabs(void)
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{
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}
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#else /* dynamic table generation */
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#if !defined(FF_TABLES)
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/* Generate the tables for the dynamic table option
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It will generally be sensible to use tables to compute finite
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field multiplies and inverses but where memory is scarse this
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code might sometimes be better. But it only has effect during
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initialisation so its pretty unimportant in overall terms.
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*/
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/* return 2 ^ (n - 1) where n is the bit number of the highest bit
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set in x with x in the range 1 < x < 0x00000200. This form is
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used so that locals within fi can be bytes rather than words
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*/
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static aes_08t hibit(const aes_32t x)
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{ aes_08t r = (aes_08t)((x >> 1) | (x >> 2));
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r |= (r >> 2);
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r |= (r >> 4);
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return (r + 1) >> 1;
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}
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/* return the inverse of the finite field element x */
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static aes_08t fi(const aes_08t x)
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{ aes_08t p1 = x, p2 = BPOLY, n1 = hibit(x), n2 = 0x80, v1 = 1, v2 = 0;
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if(x < 2) return x;
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for(;;)
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{
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if(!n1) return v1;
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while(n2 >= n1)
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{
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n2 /= n1; p2 ^= p1 * n2; v2 ^= v1 * n2; n2 = hibit(p2);
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}
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if(!n2) return v2;
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while(n1 >= n2)
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{
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n1 /= n2; p1 ^= p2 * n1; v1 ^= v2 * n1; n1 = hibit(p1);
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}
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}
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}
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#endif
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/* The forward and inverse affine transformations used in the S-box */
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#define fwd_affine(x) \
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(w = (aes_32t)x, w ^= (w<<1)^(w<<2)^(w<<3)^(w<<4), 0x63^(aes_08t)(w^(w>>8)))
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#define inv_affine(x) \
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(w = (aes_32t)x, w = (w<<1)^(w<<3)^(w<<6), 0x05^(aes_08t)(w^(w>>8)))
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static int init = 0;
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void gen_tabs(void)
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{ aes_32t i, w;
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#if defined(FF_TABLES)
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aes_08t pow[512], log[256];
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if(init) return;
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/* log and power tables for GF(2^8) finite field with
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WPOLY as modular polynomial - the simplest primitive
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root is 0x03, used here to generate the tables
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*/
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i = 0; w = 1;
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do
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{
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pow[i] = (aes_08t)w;
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pow[i + 255] = (aes_08t)w;
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log[w] = (aes_08t)i++;
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w ^= (w << 1) ^ (w & 0x80 ? WPOLY : 0);
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}
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while (w != 1);
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#else
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if(init) return;
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#endif
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for(i = 0, w = 1; i < RC_LENGTH; ++i)
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{
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t_set(r,c)[i] = bytes2word(w, 0, 0, 0);
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w = f2(w);
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}
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for(i = 0; i < 256; ++i)
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{ aes_08t b;
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b = fwd_affine(fi((aes_08t)i));
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w = bytes2word(f2(b), b, b, f3(b));
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#ifdef SBX_SET
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t_set(s,box)[i] = b;
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#endif
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#ifdef FT1_SET /* tables for a normal encryption round */
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t_set(f,n)[i] = w;
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#endif
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#ifdef FT4_SET
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t_set(f,n)[0][i] = w;
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t_set(f,n)[1][i] = upr(w,1);
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t_set(f,n)[2][i] = upr(w,2);
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t_set(f,n)[3][i] = upr(w,3);
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#endif
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w = bytes2word(b, 0, 0, 0);
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#ifdef FL1_SET /* tables for last encryption round (may also */
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t_set(f,l)[i] = w; /* be used in the key schedule) */
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#endif
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#ifdef FL4_SET
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t_set(f,l)[0][i] = w;
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t_set(f,l)[1][i] = upr(w,1);
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t_set(f,l)[2][i] = upr(w,2);
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t_set(f,l)[3][i] = upr(w,3);
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#endif
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#ifdef LS1_SET /* table for key schedule if t_set(f,l) above is */
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t_set(l,s)[i] = w; /* not of the required form */
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#endif
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#ifdef LS4_SET
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t_set(l,s)[0][i] = w;
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t_set(l,s)[1][i] = upr(w,1);
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t_set(l,s)[2][i] = upr(w,2);
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t_set(l,s)[3][i] = upr(w,3);
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#endif
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b = fi(inv_affine((aes_08t)i));
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w = bytes2word(fe(b), f9(b), fd(b), fb(b));
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#ifdef IM1_SET /* tables for the inverse mix column operation */
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t_set(i,m)[b] = w;
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#endif
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#ifdef IM4_SET
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t_set(i,m)[0][b] = w;
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t_set(i,m)[1][b] = upr(w,1);
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t_set(i,m)[2][b] = upr(w,2);
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t_set(i,m)[3][b] = upr(w,3);
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#endif
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#ifdef ISB_SET
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t_set(i,box)[i] = b;
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#endif
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#ifdef IT1_SET /* tables for a normal decryption round */
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t_set(i,n)[i] = w;
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#endif
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#ifdef IT4_SET
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t_set(i,n)[0][i] = w;
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t_set(i,n)[1][i] = upr(w,1);
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t_set(i,n)[2][i] = upr(w,2);
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t_set(i,n)[3][i] = upr(w,3);
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#endif
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w = bytes2word(b, 0, 0, 0);
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#ifdef IL1_SET /* tables for last decryption round */
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t_set(i,l)[i] = w;
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#endif
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#ifdef IL4_SET
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t_set(i,l)[0][i] = w;
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t_set(i,l)[1][i] = upr(w,1);
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t_set(i,l)[2][i] = upr(w,2);
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t_set(i,l)[3][i] = upr(w,3);
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#endif
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}
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init = 1;
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}
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#endif
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#if defined(__cplusplus)
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}
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#endif
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