1 #include <stdint.h>
2 #include <stdlib.h>
3 #include <unistd.h>
4 
5 struct expanded_key {
6     uint32_t l[16], r[16];
7 };
8 
9 void __des_setkey(const unsigned char* key, struct expanded_key* ekey);
10 void __do_des(uint32_t l_in, uint32_t r_in, uint32_t* l_out, uint32_t* r_out, uint32_t count,
11               uint32_t saltbits, const struct expanded_key* ekey);
12 
13 static struct expanded_key __encrypt_key;
14 
setkey(const char * key)15 void setkey(const char* key) {
16     unsigned char bkey[8];
17     int i, j;
18 
19     for (i = 0; i < 8; i++) {
20         bkey[i] = 0;
21         for (j = 7; j >= 0; j--, key++)
22             bkey[i] |= (uint32_t)(*key & 1) << j;
23     }
24 
25     __des_setkey(bkey, &__encrypt_key);
26 }
27 
encrypt(char * block,int edflag)28 void encrypt(char* block, int edflag) {
29     struct expanded_key decrypt_key, *key;
30     uint32_t b[2];
31     int i, j;
32     char* p;
33 
34     p = block;
35     for (i = 0; i < 2; i++) {
36         b[i] = 0;
37         for (j = 31; j >= 0; j--, p++)
38             b[i] |= (uint32_t)(*p & 1) << j;
39     }
40 
41     key = &__encrypt_key;
42     if (edflag) {
43         key = &decrypt_key;
44         for (i = 0; i < 16; i++) {
45             decrypt_key.l[i] = __encrypt_key.l[15 - i];
46             decrypt_key.r[i] = __encrypt_key.r[15 - i];
47         }
48     }
49 
50     __do_des(b[0], b[1], b, b + 1, 1, 0, key);
51 
52     p = block;
53     for (i = 0; i < 2; i++)
54         for (j = 31; j >= 0; j--)
55             *p++ = b[i] >> j & 1;
56 }
57