github.com/afumu/libc@v0.0.6/musl/src/crypt/encrypt.c (about)

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