/*
* This program implements the
* Proposed Federal Information Processing
* Data Encryption Standard.
* See Federal Register, March 17, 1975 (40FR12134)
*/
/*
* Initial permutation,
*/
static char IP[] = {
58,50,42,34,26,18,10, 2,
60,52,44,36,28,20,12, 4,
62,54,46,38,30,22,14, 6,
64,56,48,40,32,24,16, 8,
57,49,41,33,25,17, 9, 1,
59,51,43,35,27,19,11, 3,
61,53,45,37,29,21,13, 5,
63,55,47,39,31,23,15, 7,
};
/*
* Final permutation, FP = IP^(-1)
*/
static char FP[] = {
40, 8,48,16,56,24,64,32,
39, 7,47,15,55,23,63,31,
38, 6,46,14,54,22,62,30,
37, 5,45,13,53,21,61,29,
36, 4,44,12,52,20,60,28,
35, 3,43,11,51,19,59,27,
34, 2,42,10,50,18,58,26,
33, 1,41, 9,49,17,57,25,
};
/*
* Permuted-choice 1 from the key bits
* to yield C and D.
* Note that bits 8,16... are left out:
* They are intended for a parity check.
*/
static char PC1_C[] = {
57,49,41,33,25,17, 9,
1,58,50,42,34,26,18,
10, 2,59,51,43,35,27,
19,11, 3,60,52,44,36,
};
static char PC1_D[] = {
63,55,47,39,31,23,15,
7,62,54,46,38,30,22,
14, 6,61,53,45,37,29,
21,13, 5,28,20,12, 4,
};
/*
* Sequence of shifts used for the key schedule.
*/
static char shifts[] = {
1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1,
};
/*
* Permuted-choice 2, to pick out the bits from
* the CD array that generate the key schedule.
*/
static char PC2_C[] = {
14,17,11,24, 1, 5,
3,28,15, 6,21,10,
23,19,12, 4,26, 8,
16, 7,27,20,13, 2,
};
static char PC2_D[] = {
41,52,31,37,47,55,
30,40,51,45,33,48,
44,49,39,56,34,53,
46,42,50,36,29,32,
};
/*
* The C and D arrays used to calculate the key schedule.
*/
static char C[28];
static char D[28];
/*
* The key schedule.
* Generated from the key.
*/
static char KS[16][48];
/*
* The E bit-selection table.
*/
static char E[48];
static char e[] = {
32, 1, 2, 3, 4, 5,
4, 5, 6, 7, 8, 9,
8, 9,10,11,12,13,
12,13,14,15,16,17,
16,17,18,19,20,21,
20,21,22,23,24,25,
24,25,26,27,28,29,
28,29,30,31,32, 1,
};
/*
* Set up the key schedule from the key.
*/
static
setkey(key)
char *key;
{
int i, j, k;
int t;
char *ptr;
/*
* First, generate C and D by permuting
* the key. The low order bit of each
* 8-bit char is not used, so C and D are only 28
* bits apiece.
*/
for (i=0; i<28; i++) {
C[i] = key[PC1_C[i]-1];
D[i] = key[PC1_D[i]-1];
}
/*
* To generate Ki, rotate C and D according
* to schedule and pick up a permutation
* using PC2.
*/
for (i=0; i<16; i++) {
/*
* rotate.
*/
for (k=0; k<shifts[i]; k++) {
t = C[0];
ptr = C;
for (j=0; j<28-1; j++)
{
*ptr = ptr[1];
ptr++;
}
C[27] = t;
t = D[0];
ptr = D;
for (j=0; j<28-1; j++)
{
*ptr = ptr[1];
ptr++;
}
D[27] = t;
}
/*
* get Ki. Note C and D are concatenated.
*/
ptr = &KS[i][0];
for (j=0; j<24; j++) {
ptr[j] = C[PC2_C[j]-1];
ptr[j+24] = D[PC2_D[j]-28-1];
}
}
for(i=0;i<48;i++)
E[i] = e[i];
}
/*
* The 8 selection functions.
* For some reason, they give a 0-origin
* index, unlike everything else.
*/
static char S[8][64] = {
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,
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,
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,
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,
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,
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,
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,
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,
};
/*
* P is a permutation on the selected combination
* of the current L and key.
*/
static char P[] = {
16, 7,20,21,
29,12,28,17,
1,15,23,26,
5,18,31,10,
2, 8,24,14,
32,27, 3, 9,
19,13,30, 6,
22,11, 4,25,
};
/*
* The current block, divided into 2 halves.
*/
static char L[64];
#define R (L + 32)
static char tempL[32];
static char f[32];
/*
* The combination of the key and the input, before selection.
*/
static char preS[48];
/*
* The payoff: encrypt a block.
*/
static
encrypt (block, edflag)
char *block;
{
int i, ii;
register t, j, k;
/*
* First, permute the bits in the input
*/
for (j=0; j<64; j++)
L[j] = block[IP[j]-1];
/*
* Perform an encryption operation 16 times.
*/
for (ii=0; ii<16; ii++) {
/* print_bits ("L R", L); */
/*
* Set direction
*/
if (edflag)
i = 15-ii;
else
i = ii;
/*
* Save the R array,
* which will be the new L.
*/
for (j=0; j<32; j++)
tempL[j] = R[j];
/*
* Expand R to 48 bits using the E selector;
* exclusive-or with the current key bits.
*/
for (j=0; j<48; j++)
preS[j] = R[E[j]-1] ^ KS[i][j];
/*
* The pre-select bits are now considered
* in 8 groups of 6 bits each.
* The 8 selection functions map these
* 6-bit quantities into 4-bit quantities
* and the results permuted
* to make an f(R, K).
* The indexing into the selection functions
* is peculiar; it could be simplified by
* rewriting the tables.
*/
for (j=0; j<8; j++) {
t = 6*j;
k = S[j][(preS[t+0]<<5)+
(preS[t+1]<<3)+
(preS[t+2]<<2)+
(preS[t+3]<<1)+
(preS[t+4]<<0)+
(preS[t+5]<<4)];
t = 4*j;
f[t+0] = (k>>3)&01;
f[t+1] = (k>>2)&01;
f[t+2] = (k>>1)&01;
f[t+3] = (k>>0)&01;
}
/*
* The new R is L ^ f(R, K).
* The f here has to be permuted first, though.
*/
for (j=0; j<32; j++)
R[j] = L[j] ^ f[P[j]-1];
/*
* Finally, the new L (the original R)
* is copied back.
*/
for (j=0; j<32; j++)
L[j] = tempL[j];
}
/*
* The output L and R are reversed.
*/
for (j=0; j<32; j++) {
t = L[j];
L[j] = R[j];
R[j] = t;
}
/*
* The final output
* gets the inverse permutation of the very original.
*/
for (j=0; j<64; j++)
block[j] = L[FP[j]-1];
}
static
bytes_to_bits (bytes, bits)
unsigned char *bytes;
char *bits;
{
int bit, byte, value;
for (byte = 0; byte < 8; byte++)
{
value = *bytes++;
for (bit = 0; bit < 8; bit++)
*bits++ = (value >> (7-bit)) & 1;
}
}
static
bits_to_bytes (bits, bytes)
char *bits;
unsigned char *bytes;
{
int bit, byte, value;
for (byte = 0; byte < 8; byte++)
{
value = 0;
for (bit = 0; bit < 8; bit++)
value |= *bits++ << (7-bit);
*bytes++ = value;
}
}
/*
* Interface compatible with Kerberos DES implementation
*/
# include "Wrap.h"
/*ARGSUSED*/
_XdmcpAuthSetup (key, schedule)
auth_cblock key;
auth_wrapper_schedule schedule;
{
char expand_key[64];
bytes_to_bits ((unsigned char *) key, expand_key);
setkey (expand_key);
}
/*ARGSUSED*/
_XdmcpAuthDoIt (input, output, schedule, edflag)
auth_cblock input, output;
auth_wrapper_schedule schedule;
int edflag;
{
char expand_input[64];
bytes_to_bits ((unsigned char *) input, expand_input);
encrypt (expand_input, !edflag);
bits_to_bytes (expand_input, (unsigned char *) output);
}
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