twofish.c

一个提供档案及Partition作加解密的程式支援以下的加密演算法AESBlowfishCAST5SerpentTriple DESTwofishAES-BlowfishAES-TwofishAES-

/* This is an independent implementation of the encryption algorithm:   */
/*                                                                      */
/*         Twofish by Bruce Schneier and colleagues                     */
/*                                                                      */
/* which is a candidate algorithm in the Advanced Encryption Standard   */
/* programme of the US National Institute of Standards and Technology.  */
/*                                                                      */
/* Copyright in this implementation is held by Dr B R Gladman but I     */
/* hereby give permission for its free direct or derivative use subject */
/* to acknowledgment of its origin and compliance with any conditions   */
/* that the originators of the algorithm place on its exploitation.     */
/*                                                                      */
/* My thanks to Doug Whiting and Niels Ferguson for comments that led   */
/* to improvements in this implementation.                              */
/*                                                                      */
/* Dr Brian Gladman ([e-mail]) 14th January 1999     */

/* Support for multithreaded operation added by TrueCrypt Foundation */

#include "twofish.h"

#define Q_TABLES
#define M_TABLE
#define MK_TABLE
#define ONE_STEP

static char *alg_name[] = { "twofish", "twofish.c", "twofish" };

static char **cipher_name()
{
    return alg_name;
}

//u4byte  k_len;
//u4byte  l_key[40];
//u4byte  s_key[4];

/* finite field arithmetic for GF(2**8) with the modular    */
/* polynomial x^8 + x^6 + x^5 + x^3 + 1 (0x169)             */

#define G_M 0x0169

u1byte  tab_5b[4] = { 0, G_M >> 2, G_M >> 1, (G_M >> 1) ^ (G_M >> 2) };
u1byte  tab_ef[4] = { 0, (G_M >> 1) ^ (G_M >> 2), G_M >> 1, G_M >> 2 };

#define ffm_01(x)    (x)
#define ffm_5b(x)   ((x) ^ ((x) >> 2) ^ tab_5b[(x) & 3])
#define ffm_ef(x)   ((x) ^ ((x) >> 1) ^ ((x) >> 2) ^ tab_ef[(x) & 3])

u1byte ror4[16] = { 0, 8, 1, 9, 2, 10, 3, 11, 4, 12, 5, 13, 6, 14, 7, 15 };
u1byte ashx[16] = { 0, 9, 2, 11, 4, 13, 6, 15, 8, 1, 10, 3, 12, 5, 14, 7 };

u1byte qt0[2][16] = 
{   { 8, 1, 7, 13, 6, 15, 3, 2, 0, 11, 5, 9, 14, 12, 10, 4 },
    { 2, 8, 11, 13, 15, 7, 6, 14, 3, 1, 9, 4, 0, 10, 12, 5 }
};

u1byte qt1[2][16] =
{   { 14, 12, 11, 8, 1, 2, 3, 5, 15, 4, 10, 6, 7, 0, 9, 13 }, 
    { 1, 14, 2, 11, 4, 12, 3, 7, 6, 13, 10, 5, 15, 9, 0, 8 }
};

u1byte qt2[2][16] = 
{   { 11, 10, 5, 14, 6, 13, 9, 0, 12, 8, 15, 3, 2, 4, 7, 1 },
    { 4, 12, 7, 5, 1, 6, 9, 10, 0, 14, 13, 8, 2, 11, 3, 15 }
};

u1byte qt3[2][16] = 
{   { 13, 7, 15, 4, 1, 2, 6, 14, 9, 11, 3, 0, 8, 5, 12, 10 },
    { 11, 9, 5, 1, 12, 3, 13, 14, 6, 4, 7, 15, 2, 0, 8, 10 }
};
 
static u1byte qp(const u4byte n, const u1byte x)
{   u1byte  a0, a1, a2, a3, a4, b0, b1, b2, b3, b4;

    a0 = x >> 4; b0 = x & 15;
    a1 = a0 ^ b0; b1 = ror4[b0] ^ ashx[a0];
    a2 = qt0[n][a1]; b2 = qt1[n][b1];
    a3 = a2 ^ b2; b3 = ror4[b2] ^ ashx[a2];
    a4 = qt2[n][a3]; b4 = qt3[n][b3];
    return (b4 << 4) | a4;
};

#ifdef  Q_TABLES

u4byte  qt_gen = 0;
u1byte  q_tab[2][256];

#define q(n,x)  q_tab[n][x]

static void gen_qtab(void)
{   u4byte  i;

    for(i = 0; i < 256; ++i)
    {       
        q(0,i) = qp(0, (u1byte)i);
        q(1,i) = qp(1, (u1byte)i);
    }
};

#else

#define q(n,x)  qp(n, x)

#endif

#ifdef  M_TABLE

u4byte  mt_gen = 0;
u4byte  m_tab[4][256];

static void gen_mtab(void)
{   u4byte  i, f01, f5b, fef;
    
    for(i = 0; i < 256; ++i)
    {
        f01 = q(1,i); f5b = ffm_5b(f01); fef = ffm_ef(f01);
        m_tab[0][i] = f01 + (f5b << 8) + (fef << 16) + (fef << 24);
        m_tab[2][i] = f5b + (fef << 8) + (f01 << 16) + (fef << 24);

        f01 = q(0,i); f5b = ffm_5b(f01); fef = ffm_ef(f01);
        m_tab[1][i] = fef + (fef << 8) + (f5b << 16) + (f01 << 24);
        m_tab[3][i] = f5b + (f01 << 8) + (fef << 16) + (f5b << 24);
    }
};

#define mds(n,x)    m_tab[n][x]

#else

#define fm_00   ffm_01
#define fm_10   ffm_5b
#define fm_20   ffm_ef
#define fm_30   ffm_ef
#define q_0(x)  q(1,x)

#define fm_01   ffm_ef
#define fm_11   ffm_ef
#define fm_21   ffm_5b
#define fm_31   ffm_01
#define q_1(x)  q(0,x)

#define fm_02   ffm_5b
#define fm_12   ffm_ef
#define fm_22   ffm_01
#define fm_32   ffm_ef
#define q_2(x)  q(1,x)

#define fm_03   ffm_5b
#define fm_13   ffm_01
#define fm_23   ffm_ef
#define fm_33   ffm_5b
#define q_3(x)  q(0,x)

#define f_0(n,x)    ((u4byte)fm_0##n(x))
#define f_1(n,x)    ((u4byte)fm_1##n(x) << 8)
#define f_2(n,x)    ((u4byte)fm_2##n(x) << 16)
#define f_3(n,x)    ((u4byte)fm_3##n(x) << 24)

#define mds(n,x)    f_0(n,q_##n(x)) ^ f_1(n,q_##n(x)) ^ f_2(n,q_##n(x)) ^ f_3(n,q_##n(x))

#endif

static u4byte h_fun(TwofishInstance *instance, const u4byte x, const u4byte key[])
{   u4byte  b0, b1, b2, b3;

#ifndef M_TABLE
    u4byte  m5b_b0, m5b_b1, m5b_b2, m5b_b3;
    u4byte  mef_b0, mef_b1, mef_b2, mef_b3;
#endif

    b0 = extract_byte(x, 0); b1 = extract_byte(x, 1); b2 = extract_byte(x, 2); b3 = extract_byte(x, 3);

    switch(instance->k_len)
    {
    case 4: b0 = q(1, b0) ^ extract_byte(key[3],0);
            b1 = q(0, b1) ^ extract_byte(key[3],1);
            b2 = q(0, b2) ^ extract_byte(key[3],2);
            b3 = q(1, b3) ^ extract_byte(key[3],3);
    case 3: b0 = q(1, b0) ^ extract_byte(key[2],0);
            b1 = q(1, b1) ^ extract_byte(key[2],1);
            b2 = q(0, b2) ^ extract_byte(key[2],2);
            b3 = q(0, b3) ^ extract_byte(key[2],3);
    case 2: b0 = q(0,q(0,b0) ^ extract_byte(key[1],0)) ^ extract_byte(key[0],0);
            b1 = q(0,q(1,b1) ^ extract_byte(key[1],1)) ^ extract_byte(key[0],1);
            b2 = q(1,q(0,b2) ^ extract_byte(key[1],2)) ^ extract_byte(key[0],2);
            b3 = q(1,q(1,b3) ^ extract_byte(key[1],3)) ^ extract_byte(key[0],3);
    }
#ifdef  M_TABLE

    return  mds(0, b0) ^ mds(1, b1) ^ mds(2, b2) ^ mds(3, b3);

#else

    b0 = q(1, b0); b1 = q(0, b1); b2 = q(1, b2); b3 = q(0, b3);
    m5b_b0 = ffm_5b(b0); m5b_b1 = ffm_5b(b1); m5b_b2 = ffm_5b(b2); m5b_b3 = ffm_5b(b3);
    mef_b0 = ffm_ef(b0); mef_b1 = ffm_ef(b1); mef_b2 = ffm_ef(b2); mef_b3 = ffm_ef(b3);
    b0 ^= mef_b1 ^ m5b_b2 ^ m5b_b3; b3 ^= m5b_b0 ^ mef_b1 ^ mef_b2;
    b2 ^= mef_b0 ^ m5b_b1 ^ mef_b3; b1 ^= mef_b0 ^ mef_b2 ^ m5b_b3;

    return b0 | (b3 << 8) | (b2 << 16) | (b1 << 24);

#endif
};

#ifdef  MK_TABLE

#ifdef  ONE_STEP
//u4byte  mk_tab[4][256];
#else
u1byte  sb[4][256];
#endif

#define q20(x)  q(0,q(0,x) ^ extract_byte(key[1],0)) ^ extract_byte(key[0],0)
#define q21(x)  q(0,q(1,x) ^ extract_byte(key[1],1)) ^ extract_byte(key[0],1)
#define q22(x)  q(1,q(0,x) ^ extract_byte(key[1],2)) ^ extract_byte(key[0],2)
#define q23(x)  q(1,q(1,x) ^ extract_byte(key[1],3)) ^ extract_byte(key[0],3)

#define q30(x)  q(0,q(0,q(1, x) ^ extract_byte(key[2],0)) ^ extract_byte(key[1],0)) ^ extract_byte(key[0],0)
#define q31(x)  q(0,q(1,q(1, x) ^ extract_byte(key[2],1)) ^ extract_byte(key[1],1)) ^ extract_byte(key[0],1)
#define q32(x)  q(1,q(0,q(0, x) ^ extract_byte(key[2],2)) ^ extract_byte(key[1],2)) ^ extract_byte(key[0],2)
#define q33(x)  q(1,q(1,q(0, x) ^ extract_byte(key[2],3)) ^ extract_byte(key[1],3)) ^ extract_byte(key[0],3)

#define q40(x)  q(0,q(0,q(1, q(1, x) ^ extract_byte(key[3],0)) ^ extract_byte(key[2],0)) ^ extract_byte(key[1],0)) ^ extract_byte(key[0],0)
#define q41(x)  q(0,q(1,q(1, q(0, x) ^ extract_byte(key[3],1)) ^ extract_byte(key[2],1)) ^ extract_byte(key[1],1)) ^ extract_byte(key[0],1)
#define q42(x)  q(1,q(0,q(0, q(0, x) ^ extract_byte(key[3],2)) ^ extract_byte(key[2],2)) ^ extract_byte(key[1],2)) ^ extract_byte(key[0],2)
#define q43(x)  q(1,q(1,q(0, q(1, x) ^ extract_byte(key[3],3)) ^ extract_byte(key[2],3)) ^ extract_byte(key[1],3)) ^ extract_byte(key[0],3)

static gen_mk_tab(TwofishInstance *instance, u4byte key[])
{   u4byte  i;
    u1byte  by;

	u4byte *l_key = instance->l_key;
	u4byte *s_key = instance->s_key;
	u4byte *mk_tab = instance->mk_tab;

    switch(instance->k_len)