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/* This file is part of the KDE project
Copyright (C) 2001 George Staikos <staikos@kde.org>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
// FIXME: should we unroll some loops? Optimization can be done here.
/* Implementation of 16 rounds blowfish as described in:
* _Applied_Cryptography_ (c) Bruce Schneier, 1996.
*/
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "blowfish.h"
#include "blowfishtables.h"
BlowFish::BlowFish() {
_blksz = 8;
_key = 0L;
_init = false;
}
bool BlowFish::init() {
// Initialize the sboxes
for (int i = 0; i < 256; i++) {
_S[0][i] = ks0[i];
_S[1][i] = ks1[i];
_S[2][i] = ks2[i];
_S[3][i] = ks3[i];
}
uint32_t datal = 0;
uint32_t datar = 0;
uint32_t data = 0;
int j = 0;
// Update the sboxes and pbox.
for (int i = 0; i < 18; i++) {
data = 0;
for (int k = 0; k < 4; ++k) {
data = (data << 8) | ((unsigned char *)_key)[j++];
if (j >= _keylen / 8) {
j = 0;
}
}
_P[i] = P[i] ^ data;
}
for (int i = 0; i < 18; i += 2) {
encipher(&datal, &datar);
_P[i] = datal;
_P[i+1] = datar;
}
for (int j = 0; j < 4; j++) {
for (int i = 0; i < 256; i += 2) {
encipher(&datal, &datar);
_S[j][i] = datal;
_S[j][i+1] = datar;
}
}
// Nice code from gpg's implementation...
// check to see if the key is weak and return error if so
for (int i = 0; i < 255; i++) {
for (int j = i + 1; j < 256; j++) {
if ((_S[0][i] == _S[0][j]) || (_S[1][i] == _S[1][j]) ||
(_S[2][i] == _S[2][j]) || (_S[3][i] == _S[3][j])) {
return false;
}
}
}
_init = true;
return true;
}
BlowFish::~BlowFish() {
delete[] (unsigned char *)_key;
_key = 0L;
}
int BlowFish::keyLen() const {
return 448;
}
bool BlowFish::variableKeyLen() const {
return true;
}
bool BlowFish::readyToGo() const {
return _init;
}
bool BlowFish::setKey(void *key, int bitlength) {
if (bitlength <= 0 || bitlength > 448 || bitlength % 8 != 0) {
return false;
}
delete[] (unsigned char *)_key;
_key = new unsigned char[bitlength / 8];
memcpy(_key, key, bitlength / 8);
_keylen = bitlength;
return init();
}
#ifdef WORDS_BIGENDIAN
#define shuffle(x) do { \
uint32_t r = x; \
x = (r & 0xff000000) >> 24; \
x |= (r & 0x00ff0000) >> 8; \
x |= (r & 0x0000ff00) << 8; \
x |= (r & 0x000000ff) << 24; \
} while (0)
#endif
int BlowFish::encrypt(void *block, int len) {
uint32_t *d = (uint32_t *)block;
if (!_init || len % _blksz != 0) {
return -1;
}
for (int i = 0; i < len / _blksz; i++) {
#ifdef WORDS_BIGENDIAN
shuffle(*d);
shuffle(*(d + 1));
#endif
encipher(d, d + 1);
#ifdef WORDS_BIGENDIAN
shuffle(*d);
shuffle(*(d + 1));
#endif
d += 2;
}
return len;
}
int BlowFish::decrypt(void *block, int len) {
uint32_t *d = (uint32_t *)block;
if (!_init || len % _blksz != 0) {
return -1;
}
for (int i = 0; i < len / _blksz; i++) {
#ifdef WORDS_BIGENDIAN
shuffle(*d);
shuffle(*(d + 1));
#endif
decipher(d, d + 1);
#ifdef WORDS_BIGENDIAN
shuffle(*d);
shuffle(*(d + 1));
#endif
d += 2;
}
return len;
}
uint32_t BlowFish::F(uint32_t x) {
unsigned short a, b, c, d;
uint32_t y;
d = x & 0x000000ff;
x >>= 8;
c = x & 0x000000ff;
x >>= 8;
b = x & 0x000000ff;
x >>= 8;
a = x & 0x000000ff;
y = _S[0][a] + _S[1][b];
y ^= _S[2][c];
y += _S[3][d];
return y;
}
void BlowFish::encipher(uint32_t *xl, uint32_t *xr) {
uint32_t Xl = *xl, Xr = *xr, temp;
for (int i = 0; i < 16; ++i) {
Xl ^= _P[i];
Xr ^= F(Xl);
// Exchange
temp = Xl; Xl = Xr; Xr = temp;
}
// Exchange
temp = Xl; Xl = Xr; Xr = temp;
Xr ^= _P[16];
Xl ^= _P[17];
*xl = Xl;
*xr = Xr;
}
void BlowFish::decipher(uint32_t *xl, uint32_t *xr) {
uint32_t Xl = *xl, Xr = *xr, temp;
for (int i = 17; i > 1; --i) {
Xl ^= _P[i];
Xr ^= F(Xl);
// Exchange
temp = Xl; Xl = Xr; Xr = temp;
}
// Exchange
temp = Xl; Xl = Xr; Xr = temp;
Xr ^= _P[1];
Xl ^= _P[0];
*xl = Xl;
*xr = Xr;
}
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