📄 des.c
字号:
tform1( 59, 51, 43, 35, 27, 19, 11, 3)tform2( 60, 52, 44, 36, 1, 1, 1, 1)
0xFF,
/* 245 Permutation Choice 1- D0 64 * 28 */
tform1( 63, 55, 47, 39, 31, 23, 15, 7)tform2( 62, 54, 46, 38, 30, 22, 14, 6)
tform1( 61, 53, 45, 37, 29, 21, 13, 5)tform2( 28, 20, 12, 4, 1, 1, 1, 1)
0xFF,
/* 278 Permutation Choice 2 56 * 48 */
tform1( 14, 17, 11, 24, 1, 5, 3, 28)tform2( 15, 6, 21, 10, 23, 19, 12, 4)
tform1( 26, 8, 16, 7, 27, 20, 13, 2)tform2( 41, 52, 31, 37, 47, 55, 30, 40)
tform1( 51, 45, 33, 48, 44, 49, 39, 56)tform2( 34, 53, 46, 42, 50, 36, 29, 32)
0xFF
};
/* */
/* Selection Functions */
static byte s[] = {
/* S1 */
14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13,
/* S2 */
15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9,
/* S3 */
10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12,
/* S4 */
7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14,
/* S5 */
2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3,
/* S6 */
12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13,
/* S7 */
4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12,
/* S8 */
13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11
};
/* */
/*
Shift Values
*/
static byte shft[] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };
void TRANSFORM( unsigned int* in, unsigned int* out, unsigned int base_rule )
/* transform up to 64 bits according to a rule */
{
static unsigned int bits[] = { 0x8000,
0x4000,
0x2000,
0x1000,
0x0800,
0x0400,
0x0200,
0x0100,
0x0080,
0x0040,
0x0020,
0x0010,
0x0008,
0x0004,
0x0002,
0x0001 };
unsigned int outword,x,i;
i = 0;
outword = 0;
while ( (x = rules[base_rule]) != 0xFF ) {
outword <<= 1; /* shift the result left one bit */
/* (x & 060) >> 4 is index into in */
/* x & 017 is bit # in */
outword |= ( (in[ (x & 0x30 ) >> 4 ] & bits[ x & 0x0f ]) ? 1 : 0 );
if (x & 0x80) {
out[i] = outword;
i++;
};
base_rule++;
}
}
/* */
unsigned int bf( unsigned int x, unsigned int p1, unsigned int p2)
/* get bit field from bit p1 to bit p2 */
/* bits are numbered msb=0, lsb=15 */
{
return ( (x >> 15-p2) & ~(~0 << p2-p1+1) );
}
#define s_function(s_value,in) s[ s_value + map[in] ]
void SELECT( unsigned int* in, unsigned int* out )
{
static byte map[] = {
0, 16, 1, 17, 2, 18, 3, 19, 4, 20, 5, 21, 6, 22, 7, 23,
8, 24, 9, 25, 10, 26, 11, 27, 12, 28, 13, 29, 14, 30, 15, 31,
32, 48, 33, 49, 34, 50, 35, 51, 36, 52, 37, 53, 38, 54, 39, 55,
40, 56, 41, 57, 42, 58, 43, 59, 44, 60, 45, 61, 46, 62, 47, 63
};
unsigned int hi, lo;
hi = s_function( 0, bf(in[0],0,5) ) << 4 |
s_function( 64, bf(in[0],6,11) ) ;
lo = s_function( 128, ((bf(in[0],12,15) << 2) | bf(in[1],0,1))) << 4 |
s_function( 192, bf(in[1],2,7) );
lo = lo & 0xFF;
out[0] = hi * 0x100 + lo;
hi = s_function( 256, bf(in[1],8,13) ) << 4 |
s_function( 320, ((bf(in[1],14,15) << 4) | bf(in[2],0,3))) ;
lo = s_function( 384, bf(in[2],4,9) ) << 4 |
s_function( 448, bf(in[2],10,15));
lo = lo & 0xFF;
out[1] = hi * 0x100 + lo;
}
/* */
void SETKS( unsigned int* key, unsigned int* subkeys )
{
unsigned int i,
y,
z,
C[2], /* key permutation register 28 bits */
D[2], /* key permutation register 28 bits */
CD[4]; /* combined key permutation register 56 bits */
TRANSFORM( key, C, PC1A );
TRANSFORM( key, D, PC1B );
for ( i = 0 ; i <= 15 ; i++ )
{
y = shft[i];
switch(y)
{
case 1 : z = bf(C[0],0,0);
C[0] = bf(C[0],1,15) << 01; /* 1.0.2 */
C[0] |= bf(C[1],0,0);
C[1] = bf(C[1],1,11) << 05; /* 1.0.2 */
C[1] |= z << 4;
z = bf(D[0],0,0);
D[0] = bf(D[0],1,15) << 01; /* 1.0.2 */
D[0] |= bf(D[1],0,0);
D[1] = bf(D[1],1,11) << 05; /* 1.0.2 */
D[1] |= z << 4;
break;
case 2 : z = bf(C[0],0,1);
C[0] = bf(C[0],2,15) << 02; /* 1.0.2 */
C[0] |= bf(C[1],0,1);
C[1] = bf(C[1],2,11) << 06; /* 1.0.2 */
C[1] |= z << 4;
z = bf(D[0],0,1);
D[0] = bf(D[0],2,15) << 02; /* 1.0.2 */
D[0] |= bf(D[1],0,1);
D[1] = bf(D[1],2,11) << 06; /* 1.0.2 */
D[1] |= z << 4;
break;
}
CD[0] = C[0];
CD[1] = bf(C[1],0,11) << 4 | bf(D[0],0,3);
CD[2] = bf(D[0],4,15) << 4 | bf(D[1],0,3);
CD[3] = bf(D[1],4,15) << 4;
TRANSFORM( CD, &subkeys[3*i], PC2 );
}
}
/* */
void DES( unsigned int* text, unsigned int* key, unsigned int encrypt, unsigned int* work)
{
int start = 15, /* defaults are set to decode values */
end_ = -1,
incr = -1;
unsigned int L[4], /* leftmost (and rightmost) 32 bits */
TEMP1[4],
TEMP2[4];
int i,xq;
if ( encrypt )
{
start = 0;
end_ = 16;
incr = 1;
}
TRANSFORM( text, L, IP );
if ( work[0] != key[0] || /* if the key in the work area is the same as */
work[1] != key[1] || /* the supplied key, the subkeys in the sork */
work[2] != key[2] || /* area have already been calculated */
work[3] != key[3] )
{
work[0] = key[0];
work[1] = key[1];
work[2] = key[2];
work[3] = key[3];
SETKS( key, &work[4] );
}
i = start;
do
{
TRANSFORM( &L[2], TEMP1, E );
xq = 3*i + 4;
TEMP2[0] = TEMP1[0] ^ work[xq++];
TEMP2[1] = TEMP1[1] ^ work[xq++];
TEMP2[2] = TEMP1[2] ^ work[xq++];
SELECT( TEMP2, TEMP1 );
TRANSFORM( TEMP1, TEMP2, P );
TEMP1[0] = TEMP2[0] ^ L[0];
TEMP1[1] = TEMP2[1] ^ L[1];
L[0] = L[2]; /* L ':=' R for 2 */
L[1] = L[3];
L[2] = TEMP1[0]; /* R ':=' TEMP1 for 2 */
L[3] = TEMP1[1];
i += incr;
}
while (i != end_);
TEMP1[2] = L[0]; /* TEMP1[2] ':=' L for 2 */
TEMP1[3] = L[1];
TRANSFORM( TEMP1, text, IP_1 );
}
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