2 * des.c - data encryption standard algo
4 * author: hackbard@hackdaworld.dyndns.org
12 u8 key_perm_table[DES_INITIAL_KEY_LEN]={
13 57,49,41,33,25,17,9,1,58,50,42,34,26,18,
14 10,2,59,51,43,35,27,18,11,3,60,52,44,36,
15 63,55,47,39,31,23,15,7,62,54,46,38,30,22,
16 14,6,61,53,45,37,29,21,13,5,28,20,12,4
19 u8 rot_per_round_table[DES_SUBKEYS]={
20 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
23 u8 subkey_perm_table[DES_SUBKEY_LEN]={
24 14,17,11,24,1,5,3,28,15,6,21,10,
25 23,19,12,4,26,8,16,7,27,20,13,2,
26 41,52,31,37,47,55,30,40,51,45,33,48,
27 44,49,39,56,34,53,46,42,50,36,29,32
30 u8 data_perm_table[DES_DATA_BLOCK_LEN]={
31 58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4,
32 62,54,46,38,30,22,14,6,64,56,48,40,32,24,16,8,
33 57,49,41,33,25,17,9,1,59,51,43,35,27,19,11,3,
34 61,53,45,37,29,21,13,5,63,55,47,39,31,23,15,7
37 u8 data_expansion_table[DES_SUBKEY_LEN]={
38 32,1,2,3,4,5,4,5,6,7,8,9,
39 8,9,10,11,12,13,12,13,14,15,16,17,
40 16,17,18,19,20,21,20,21,22,23,24,25,
41 24,25,26,27,28,29,28,29,30,31,32,1
44 u8 sbox[DES_SBOXES][DES_SBOX_LEN]={
45 {14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7,
46 0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8,
47 4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0,
48 15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13},
49 {15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10,
50 3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5,
51 0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15,
52 13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9},
53 {10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8,
54 13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1,
55 13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7,
56 1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12},
57 {7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15,
58 13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9,
59 10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4,
60 3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14},
61 {2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9,
62 14,11,2,12,4,7,13,1,5,0,15,10,3,9.8,6,
63 4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14,
64 11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3},
65 {12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11,
66 10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8,
67 9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6,
68 4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13},
69 {4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1,
70 13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6,
71 1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2,
72 6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12},
73 {13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7,
74 1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2,
75 7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8,
76 2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11}
79 u8 pbox[DES_PBOX_LEN]={
80 16,7,20,21,29,12,28,17,1,15,23,26,5,18,31,10,
81 2,8,24,14,32,27,3,9,19,13,30,6,22,11,4,25
84 u8 data_final_perm_table[DES_DATA_BLOCK_LEN]={
85 40,8,48,16,56,24,64,32,39,7,47,15,55,23,63,31,
86 38,6,46,14,54,22,62,30,37,5,45,13,53,21,61,29,
87 36,4,44,12,52,20,60,28,35,3,43,11,51,19,59,27,
88 34,2,42,10,50,18,58,26,33,1,41,9,49,17,57,25
91 int rotate_right(u8 *obj) {
92 u8 mid=obj[3],tmp=obj[6];
95 obj[i]=obj[i]>>1|((obj[i-1]&1)<<7);
96 obj[3]=(obj[3]&0xf)>>1|((tmp&1)<<3);
97 obj[3]|=(((obj[2]&1)<<7)|((mid&0xe0)>>1));
99 obj[i]=obj[i]>>1|((obj[i-1]&1)<<7);
100 obj[0]=obj[0]>>1|((mid&0x10)<<3);
104 int rotate_left(u8 *obj) {
105 u8 mid=obj[3],tmp=obj[0];
108 obj[i]=obj[i]<<1|(obj[i+1]>>7);
109 obj[3]=((obj[3]&0xf0)<<1)|((tmp&0x80)>>3);
110 obj[3]|=(((mid&7)<<1)|(obj[4]>>7));
112 obj[i]=(obj[i]<<1)|(obj[i+1]>>7);
113 obj[6]=obj[6]<<1|((mid&8)>>3);
115 for(i=0;i<7;i++) printf("%02x ",obj[i]);
120 int table_trans(u8 *src,u8 *final,u8 *table,int len) {
122 memset(final,0,len/8);
124 final[i/8]|=((((src[(table[i]-1)/8])>>((8-(table[i])%8)&7))&1)<<(7-i%8));
128 int subkey_trans(u8 *key,int round) {
130 for(i=0;i<rot_per_round_table[round];i++)
135 int compute_subkeys(u8 *key0,u8 subkey[DES_SUBKEYS][DES_SUBKEY_LEN/8]) {
137 u8 key0_56[DES_INITIAL_KEY_LEN/8];
138 /* initial permutation of key */
139 table_trans(key0,key0_56,key_perm_table,DES_INITIAL_KEY_LEN);
140 for(i=0;i<7;i++) printf("%02x ",key0_56[i]);
142 for(i=0;i<DES_SUBKEYS;i++) {
143 /* split and rotate key_056 */
144 subkey_trans(key0_56,i);
145 /* chose 48 bits as a subkey */
146 table_trans(key0_56,subkey[i],subkey_perm_table,DES_SUBKEY_LEN);
151 int data_s_and_p(u8 *data) {
152 u8 s[DES_DATA_BLOCK_LEN/(8*2)];
153 memset(s,0,DES_DATA_BLOCK_LEN/(8*2));
154 s[0]=sbox[0][16*(((data[0]&0x80)>>6)|((data[0]&4)>>2))+((data[0]&0x78)>>3)]<<4;
155 s[0]|=sbox[1][16*((data[0]&2)|((data[1]&0x10)>>4))+(((data[0]&1)<<3)|(data[1]&0xe0)>>5)];
156 s[1]=sbox[2][16*(((data[1]&8)>>2)|((data[2]&0x40)>>6))+(((data[1]&7)<<1)|((data[2]&0x80)>>7))]<<4;
157 s[1]|=sbox[3][16*(((data[2]&0x20)>>4)|(data[2]&1))+((data[2]&0x1e)>>1)];
158 s[2]=sbox[4][16*(((data[3]&0x80)>>6)|((data[3]&4)>>2))+((data[3]&0x78)>>3)]<<4;
159 s[2]|=sbox[5][16*((data[3]&2)|((data[4]&0x10)>>4))+(((data[3]&1)<<3)|(data[4]&0xe0)>>5)];
160 s[3]=sbox[6][16*(((data[4]&8)>>2)|((data[5]&0x40)>>6))+(((data[4]&7)<<1)|((data[5]&0x80)>>7))]<<4;
161 s[3]|=sbox[7][16*(((data[5]&0x20)>>4)|(data[5]&1))+((data[5]&0x1e)>>1)];
162 table_trans(s,data,pbox,DES_PBOX_LEN);
166 int progress_data(u8 *data,u8 *crypted,u8 subkey[DES_SUBKEYS][DES_SUBKEY_LEN/8],u8 mode) {
168 u8 permuted_data[DES_DATA_BLOCK_LEN/8];
169 u8 left[DES_DATA_BLOCK_LEN/(2*8)];
170 u8 right[DES_DATA_BLOCK_LEN/(2*8)];
171 u8 tmp[DES_DATA_BLOCK_LEN/(2*8)];
173 /* initial permutation */
174 table_trans(data,permuted_data,data_perm_table,DES_DATA_BLOCK_LEN);
175 memcpy(left,permuted_data,DES_DATA_BLOCK_LEN/(2*8));
176 memcpy(right,permuted_data+DES_DATA_BLOCK_LEN/(2*8),DES_DATA_BLOCK_LEN/(2*8));
177 for(i=0;i<DES_SUBKEYS;i++){
178 /* expand right data to 48 bit */
179 table_trans(right,permuted_data,data_expansion_table,DES_SUBKEY_LEN);
180 /* xor with subkey */
181 for(j=0;j<DES_SUBKEY_LEN/8;j++) permuted_data[j]^=subkey[mode&MODE_CRYPT?i:DES_SUBKEYS-1-i][j];
182 /* sbox substitutions and pbox permutations */
183 data_s_and_p(permuted_data);
184 /* xor with left data */
185 memcpy(tmp,right,DES_DATA_BLOCK_LEN/(2*8));
186 for(j=0;j<DES_DATA_BLOCK_LEN/(2*8);j++)
187 right[j]=permuted_data[j]^left[j];
188 /* switch left and right data - not for last round */
189 if(i!=15) memcpy(left,tmp,DES_DATA_BLOCK_LEN/(2*8));
191 /* merge and do final permutation */
192 memcpy(permuted_data,left,DES_DATA_BLOCK_LEN/(2*8));
193 memcpy(permuted_data+DES_DATA_BLOCK_LEN/(2*8),right,DES_DATA_BLOCK_LEN/(8*2));
194 table_trans(permuted_data,crypted,data_final_perm_table,DES_DATA_BLOCK_LEN);
198 int des_crypt_decrypt(u8 *src,u8 *final,u8 *key,int len,u8 mode) {
199 u8 subkey[DES_SUBKEYS][DES_SUBKEY_LEN/8];
201 /* compute the subkeys:
202 - initial key transformation: 64bit -> 56bit
204 - split 56bit key -> 28bit - 28bit
205 - rotate these to the left (rotation depends on round)
206 - merge them again -> 56bit
207 - do permuted choice -> 56bit -> 48 bit, the subkey
210 compute_subkeys(key,subkey);
213 printf("subkey %d: ",i);
214 for(j=0;j<6;j++) printf("%02x ",subkey[i][j]);
217 /* split data to 64bit blocks, and crypt/decrypt each block
218 depending on mode (CBC/ECB):
219 - initial data transformation
221 - split 64bit data -> 32bit - 32bit
222 - expand right data block
223 - xor right block with subkey i (or 15-i)
224 - do sbox and pbox permutations
225 - xor result with left data block
226 - switch left and right data block (not for last cycle)
228 - do final permutation
230 for(i=0;i<len/8;i++) {
231 if((mode&MODE_CBC)&&(mode&MODE_CRYPT)&&(i!=0))
232 for(j=0;j<8;j++) src[i*8+j]^=final[(i-1)*8+j];
233 progress_data(src+i*8,final+i*8,subkey,mode);
234 if((mode&MODE_CBC)&&(mode&MODE_DECRYPT)&&(i!=0))
235 for(j=0;j<8;j++) final[(i*8)+j]^=src[(i-1)*8+j];
240 int des_encrypt(u8 *plain,u8 *crypted,u8 *key,int len,u8 mode) {
241 des_crypt_decrypt(plain,crypted,key,len,MODE_CRYPT|mode);
245 int des_decrypt(u8 *crypted,u8 *plain,u8 *key,int len,u8 mode) {
246 des_crypt_decrypt(crypted,plain,key,len,MODE_DECRYPT|mode);