2 * des.c - data encryption standard algo
4 * author: hackbard@hackdaworld.dyndns.org
10 u8 key_perm_table[DES_SUBKEY_LEN]={
11 57,49,41,33,25,17,9,1,58,50,42,34,26,18,
12 10,2,59,51,43,35,27,18,11,3,60,52,44,36,
13 63,55,47,39,31,23,15,7,62,54,46,38,30,22,
14 14,6,61,53,45,37,29,21,13,5,28,20,12,4
17 u8 rot_per_round_table[DES_SUBKEYS]={
18 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
21 u8 subkey_perm_table[DES_SUBKEY_LEN]={
22 14,17,11,24,1,5,3,28,15,6,21,10,
23 23,19,12,4,26,8,16,7,27,20,13,2,
24 41,52,31,37,47,55,30,40,51,45,33,48,
25 44,49,39,56,34,53,46,42,50,36,29,32
28 u8 data_perm_table[DES_DATA_BLOCK_LEN]={
29 58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4,
30 62,54,46,38,30,22,14,6,64,56,48,40,32,24,16,8,
31 57,49,41,33,25,17,9,1,59,51,43,35,27,19,11,3,
32 61,53,45,37,29,21,13,5,63,55,47,39,31,23,15,7
35 u8 data_expansion_table[DES_SUBKEY_LEN]={
36 32,1,2,3,4,5,4,5,6,7,8,9,
37 8,9,10,11,12,13,12,13,14,15,16,17,
38 16,17,18,19,20,21,20,21,22,23,24,25,
39 24,25,26,27,28,29,28,29,30,31,32,1
42 u8 sbox[DES_SBOXES][DES_SBOX_LEN]={
43 {14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7,
44 0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8,
45 4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0,
46 15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13},
47 {15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10,
48 3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5,
49 0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15,
50 13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9},
51 {10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8,
52 13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1,
53 13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7,
54 1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12},
55 {7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15,
56 13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9,
57 10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4,
58 3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14},
59 {2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9,
60 14,11,2,12,4,7,13,1,5,0,15,10,3,9.8,6,
61 4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14,
62 11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3},
63 {12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11,
64 10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8,
65 9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6,
66 4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13},
67 {4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1,
68 13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6,
69 1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2,
70 6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12},
71 {13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7,
72 1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2,
73 7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8,
74 2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
77 u8 pbox[DES_PBOX_LEN]={
78 16,7,20,21,29,12,28,17,1,15,23,26,5,18,31,10,
79 2,8,24,14,32,27,3,9,19,13,30,6,22,11,4,25
82 int rotate_right(u8 *obj,int len) {
84 while(--len) obj[len]=obj[len]>>1|((obj[len-1]&1)<<7);
85 obj[0]=obj[0]>>1|((tmp&1)<<7);;
89 int rotate_left(u8 *obj,int len) {
92 for(i=0;i<len-1;i++) obj[i]=obj[i]<<1|(obj[j+1]>>7);
93 obj[len-1]=obj[len-1]<<1|(tmp>>7);
99 u8 new[DES_INITIAL_KEY_LEN/8];
100 memset(new,0,DES_INITIAL_KEY_LEN/8];
101 for(i=0;i<DES_INITIAL_KEY_LEN;i++)
102 new[i/8]|=((((key[(key_perm_table[i]-1)/8)]>>((8-key_perm_table[i]%8)&7))&1)<<(7-i%8));
103 memcpy(key,new,DES_INITIAL_KEY_LEN);
107 int subkey_trans(u8 *key,int round) {
109 for(i=0;i<rot_per_round_table[round];i++) {
110 rotate_left(key,DES_INITIAL_KEY_LEN/(8*2));
111 rotate_left(key+DES_INITIAL_KEY_LEN/(8*2),DES_INITIAL_KEY_LEN/(8*2));
116 int subkey_perm(u8 *key,u8 *pc) {
118 memset(pc,0,DES_SUBKEY_LEN/8);
119 for(i=0;i<DES_SUBKEY_LEN;i++)
120 pc[i/8]|=((((key[subkey_perm_table[i]-1)/8]>>((8-subkey_perm_table[i]%8)&7))&1)<<(7-i%8));
124 int compute_subkeys(u8 *key0,u8 **subkey) {
127 for(i=0;i<DES_SUBKEYS;i++) {
128 subkey_trans(key0;i);
129 subkey_perm(key0,subkey[i]);
134 int data_perm(u8 *plain,u8 *pd) {
136 memset(pd,0,DES_DATA_BLOCK_LEN/8);
137 for(i=0;i<DES_DATA_BLOCK_LEN;i++)
138 pd[i/8]|=((((plain[data_perm_table[i]-1)/8]>>((8-data_perm_table[i]%8)&7))&1)<<(7-i%8));
142 int data_expansion_perm(u8 *right,u8 expanded) {
144 memset(expanded,0,DES_SUBKEY_LEN);
145 for(i=0;i<DES_SUBKEY_LEN;i++)
146 expanded[i/8]|=((((right[data_expansion_table[i]-1)/8]>>((8-data_expansion_table[i]%8)&7))&1)<<(7-i%8));
150 int get_sbox_value(u8 *data,int offset,int len,int box) {
152 tmp=((offset%8)==0)?data[offset/8]>>(8-len):((data[offset/8]&((1<<(offset%8))-1))<<(offset%8))|(data[(offset/8)+1]>>(len-(8-(offset%8))));
153 return(sbox[box][(tmp&1|(tmp&(1<<(len-1))<<1))*16+(tmp&((1<<(len-1))-1)>>1)]);
156 int data_s_and_p(u8 *data) {
157 u8 s[DES_DATA_BLOCK_LEN/2];
158 u8 p[DES_DATA_BLOCK_LEN/2];
160 for(i=0;i<DES_SBOXES;i++)
161 s[i]=get_sbox_value(data,i*(DES_SUBKEY_LEN/DES_SBOXES),(DES_SUBKEY_LEN/DES_SBOXES),i);
166 int progress_data(u8 *data,u8 **subkey,u8 mode) {
168 u8 pd[DES_DATA_BLOCK_LEN];
169 u8 left[DES_DATA_BLOCK_LEN/(2*8)];
170 u8 right[DES_DATA_BLOCK_LEN/(2*8)];
171 u8 expanded[DES_SUBKEY_LEN];
174 memcpy(left,pd,DES_DATA_BLOCK_LEN/(2*8));
175 memcpy(right,pd+DES_DATA_BLOCK_LEN/(2*8),DES_DATA_BLOCK_LEN/(2*8));
176 for(i=0;i<DES_SUBKEYS;i++){
177 data_expansion_perm(right,expanded);
178 for(j=0;j<DES_SUBKEY_LEN;j++) expanded[j]^=subkey[mode&MODE_CRYPT?i:DES_SUBKEYS-1-i][j];
179 data_s_and_p(expanded);
186 int des_crypt_decrypt(u8 *plain,u8 *crypted,u8 *key,int len,u8 mode) {
187 u8 subkey[DES_SUBKEYS][DES_SUBKEY_LEN/8];
190 /* compute the subkeys:
191 - initial key transformation: 64bit -> 56bit
193 - split 56bit key -> 28bit - 28bit
194 - rotate these to the left (rotation depends on round)
195 - merge them again -> 56bit
196 - do permuted choice -> 56bit -> 48 bit, the subkey
199 compute_subkeys(key,subkey);
200 /* split data to 64bit blocks, and crypt/decrypt each block
201 depending on mode (CBC/ECB):
202 - initial data transformation
204 - split 64bit data -> 32bit - 32bit
205 - expand right data block
206 - xor right block with subkey i (or 15-i)
207 - do sbox and pbox permutations
208 - xor result with left data block
209 - switch left and right data block (not for last cycle)
211 - do final permutation
214 /* for all data do: (not yet ready) */
215 progress_data(plain,subkey,mode);
220 int des_crypt(u8 *plain,u8 *crypted,u8 *key,int len,MODE_CRYPT) {
225 int des_decrypt(u8 *crypted,u8 *plain,u8 *key,int len,MODE_DECRYPT) {