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/*
*
* Blowfish.c : Blowfish implementation
*
* Written in 2008 by Dwayne C. Litzenberger <dlitz@dlitz.net>
*
* =======================================================================
* The contents of this file are dedicated to the public domain. To the extent
* that dedication to the public domain is not available, everyone is granted a
* worldwide, perpetual, royalty-free, non-exclusive license to exercise all
* rights associated with the contents of this file for any purpose whatsoever.
* No rights are reserved.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
* =======================================================================
*
* Country of origin: Canada
*
* The Blowfish algorithm is documented at
* http://www.schneier.com/paper-blowfish-fse.html
*/
#include "pycrypto_common.h"
#include "Blowfish-tables.h"
#include <assert.h>
#include <string.h>
#define MODULE_NAME _Blowfish
#define BLOCK_SIZE 8 /* 64-bit block size */
#define KEY_SIZE 0 /* variable key size */
#define BLOWFISH_MAGIC 0xf9d565deu
typedef struct {
uint32_t magic;
/* P permutation */
uint32_t P[18];
/* Subkeys (S-boxes) */
uint32_t S1[256];
uint32_t S2[256];
uint32_t S3[256];
uint32_t S4[256];
} Blowfish_state;
/* The Blowfish round function F. Everything is taken modulo 2**32 */
#define F(a, b, c, d) (((a) + (b)) ^ (c)) + (d)
static inline uint32_t bytes_to_word(const unsigned char *in)
{
/* big endian */
return (in[0] << 24) | (in[1] << 16) | (in[2] << 8) | in[3];
}
static inline void word_to_bytes(uint32_t w, unsigned char *out)
{
/* big endian */
out[0] = (w >> 24) & 0xff;
out[1] = (w >> 16) & 0xff;
out[2] = (w >> 8) & 0xff;
out[3] = w & 0xff;
}
static inline void inline_encrypt(Blowfish_state *self, uint32_t *pxL, uint32_t *pxR)
{
int i;
uint32_t xL = *pxL;
uint32_t xR = *pxR;
uint32_t tmp;
for (i = 0; i < 16; i++) {
xL ^= self->P[i];
/* a || b || c || d = xL (big endian) */
xR ^= F(self->S1[(xL >> 24) & 0xff], /* S1[a] */
self->S2[(xL >> 16) & 0xff], /* S2[b] */
self->S3[(xL >> 8) & 0xff], /* S3[c] */
self->S4[xL & 0xff]); /* S4[d] */
/* Swap xL, xR */
tmp = xL; xL = xR; xR = tmp;
}
/* Swap xL, xR */
tmp = xL; xL = xR; xR = tmp;
xR ^= self->P[16];
xL ^= self->P[17];
*pxL = xL;
*pxR = xR;
}
static inline void inline_decrypt(Blowfish_state *self, uint32_t *pxL, uint32_t *pxR)
{
int i;
uint32_t xL = *pxL;
uint32_t xR = *pxR;
uint32_t tmp;
xL ^= self->P[17];
xR ^= self->P[16];
/* Swap xL, xR */
tmp = xL; xL = xR; xR = tmp;
for (i = 15; i >= 0; i--) {
/* Swap xL, xR */
tmp = xL; xL = xR; xR = tmp;
/* a || b || c || d = xL (big endian) */
xR ^= F(self->S1[(xL >> 24) & 0xff], /* S1[a] */
self->S2[(xL >> 16) & 0xff], /* S2[b] */
self->S3[(xL >> 8) & 0xff], /* S3[c] */
self->S4[xL & 0xff]); /* S4[d] */
xL ^= self->P[i];
}
*pxL = xL;
*pxR = xR;
}
static void Blowfish_encrypt(Blowfish_state *self, const unsigned char *in, unsigned char *out)
{
uint32_t xL, xR;
/* Make sure the object is initialized */
assert(self->magic == BLOWFISH_MAGIC);
/* big endian */
xL = bytes_to_word(in);
xR = bytes_to_word(in+4);
inline_encrypt(self, &xL, &xR);
/* big endian */
word_to_bytes(xL, out);
word_to_bytes(xR, out+4);
}
static void Blowfish_decrypt(Blowfish_state *self, const unsigned char *in, unsigned char *out)
{
uint32_t xL, xR;
/* Make sure the object is initialized */
assert(self->magic == BLOWFISH_MAGIC);
/* big endian */
xL = bytes_to_word(in);
xR = bytes_to_word(in+4);
inline_decrypt(self, &xL, &xR);
/* big endian */
word_to_bytes(xL, out);
word_to_bytes(xR, out+4);
}
static void Blowfish_init(Blowfish_state *self, const unsigned char *key, int keylen)
{
uint32_t word;
int i;
uint32_t xL, xR;
self->magic = 0;
if (keylen < 1) {
PyErr_SetString(PyExc_ValueError, "Key cannot be empty");
return;
} else if (keylen > 56) {
PyErr_SetString(PyExc_ValueError, "Maximum key size is 448 bits");
return;
}
/* Initialize the P-array with the digits of Pi, and XOR it with the key */
word = 0;
for (i = 0; i < 18*4; i++) {
word = (word << 8) | key[i % keylen];
if ((i & 3) == 3) {
self->P[i >> 2] = initial_P[i >> 2] ^ word;
word = 0;
}
}
/* Initialize the S-boxes with more digits of Pi */
memcpy(self->S1, initial_S1, 256*sizeof(uint32_t));
memcpy(self->S2, initial_S2, 256*sizeof(uint32_t));
memcpy(self->S3, initial_S3, 256*sizeof(uint32_t));
memcpy(self->S4, initial_S4, 256*sizeof(uint32_t));
/* Stir the subkeys */
xL = xR = 0;
for (i = 0; i < 18; i += 2) {
inline_encrypt(self, &xL, &xR);
self->P[i] = xL;
self->P[i+1] = xR;
}
for (i = 0; i < 256; i += 2) {
inline_encrypt(self, &xL, &xR);
self->S1[i] = xL;
self->S1[i+1] = xR;
}
for (i = 0; i < 256; i += 2) {
inline_encrypt(self, &xL, &xR);
self->S2[i] = xL;
self->S2[i+1] = xR;
}
for (i = 0; i < 256; i += 2) {
inline_encrypt(self, &xL, &xR);
self->S3[i] = xL;
self->S3[i+1] = xR;
}
for (i = 0; i < 256; i += 2) {
inline_encrypt(self, &xL, &xR);
self->S4[i] = xL;
self->S4[i+1] = xR;
}
self->magic = BLOWFISH_MAGIC;
}
#define block_state Blowfish_state
#define block_init Blowfish_init
#define block_encrypt Blowfish_encrypt
#define block_decrypt Blowfish_decrypt
#include "block_template.c"
/* vim:set ts=4 sw=4 sts=4 expandtab: */
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