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/*
Copyright (C) 2008 Luigi Auriemma
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.
This program 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 General Public License for more details.
http://www.gnu.org/licenses/gpl-2.0.txt
*/
// modified by Luigi Auriemma for emulating the shameful customizations of MagicISO
/*
This code has been found on the website
http://www.di-mgt.com.au/crypto.html
The following is a small explanation from the website author:
Here is Bruce Schneier's code in C for his Blowfish algorithm. This version is fully ANSI compliant and contains the "missing" P-box values omitted from the book.
...
This code may be freely distributed.
Updated 29 July 2003: thanks to Mehul Motani for pointing out an error in the code for readDataLine().
*/
#include <stdio.h>
#include "blowfish.h"
#include "bf_tab.h"
#define N 16
#define noErr 0
#define DATAERROR -1
#define KEYBYTES 8
uint32_t F(blf_ctx *bc, uint32_t x)
{
uint32_t a;
uint32_t b;
uint32_t c;
uint32_t d;
uint32_t y;
d = x & 0x00FF;
x >>= 8;
c = x & 0x00FF;
x >>= 8;
b = x & 0x00FF;
x >>= 8;
a = x & 0x00FF;
y = bc->S[0][a] + bc->S[1][b];
y = y ^ bc->S[2][c];
y = y + bc->S[3][d];
return y ^ 0x28799a;
}
void Blowfish_encipher(blf_ctx *bc, uint32_t *xl, uint32_t *xr)
{
uint32_t Xl;
uint32_t Xr;
uint32_t temp;
short i;
Xl = *xl;
Xr = *xr;
for (i = 0; i < N; ++i)
{
Xl = Xl ^ bc->P[i];
Xr = F(bc, Xl) ^ Xr;
Xr ^= 0x3fbe82a9;
temp = Xl;
Xl = Xr;
Xr = temp;
}
temp = Xl;
Xl = Xr;
Xr = temp;
Xr = Xr ^ bc->P[N];
Xl = Xl ^ bc->P[N + 1];
*xl = Xl;
*xr = Xr;
}
void Blowfish_decipher(blf_ctx *bc, uint32_t *xl, uint32_t *xr)
{
uint32_t Xl;
uint32_t Xr;
uint32_t temp;
short i;
Xl = *xl;
Xr = *xr;
for (i = N + 1; i > 1; --i)
{
Xl = Xl ^ bc->P[i];
Xr = F(bc, Xl) ^ Xr;
Xr ^= 0x3fbe82a9;
/* Exchange Xl and Xr */
temp = Xl;
Xl = Xr;
Xr = temp;
}
/* Exchange Xl and Xr */
temp = Xl;
Xl = Xr;
Xr = temp;
Xr = Xr ^ bc->P[1];
Xl = Xl ^ bc->P[0];
*xl = Xl;
*xr = Xr;
}
short InitializeBlowfish(blf_ctx *bc, unsigned char key[], int keybytes)
{
short i;
short j;
short k;
uint32_t data;
uint32_t datal;
uint32_t datar;
/* initialise p & s-boxes without file read */
for (i = 0; i < N+2; i++)
{
bc->P[i] = 0; //bfp[i];
}
for (i = 0; i < 256; i++)
{
bc->S[0][i] = ks0[i];
bc->S[1][i] = ks1[i];
bc->S[2][i] = ks2[i];
bc->S[3][i] = ks3[i];
}
j = 0;
for (i = 0; i < N + 2; ++i)
{
data = 0x00000000;
for (k = 0; k < 4; ++k)
{
data = (data << 8) | (char)key[j];
j = j + 1;
if (j >= keybytes)
{
j = 0;
}
}
bc->P[i] = bc->P[i] ^ data;
}
datal = 0x00000000;
datar = 0x00000000;
for (i = 0; i < N + 2; i += 2)
{
Blowfish_encipher(bc, &datal, &datar);
bc->P[i] = datal;
bc->P[i + 1] = datar;
}
for (i = 0; i < 4; ++i)
{
for (j = 0; j < 256; j += 2)
{
Blowfish_encipher(bc, &datal, &datar);
bc->S[i][j] = datal;
bc->S[i][j + 1] = datar;
}
}
return 0;
}
void blf_key (blf_ctx *c, unsigned char *k, int len)
{
InitializeBlowfish(c, k, len);
}
void blf_enc(blf_ctx *c, uint32_t *data, int blocks)
{
uint32_t *d;
int i;
d = data;
for (i = 0; i < blocks; i++)
{
Blowfish_encipher(c, d, d+1);
d += 2;
}
}
void blf_dec(blf_ctx *c, uint32_t *data, int blocks)
{
uint32_t *d;
int i;
d = data;
for (i = 0; i < blocks; i++)
{
Blowfish_decipher(c, d, d+1);
d += 2;
}
}
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