musl/src/crypt/encrypt.c

#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>

#include "crypt_des.h"

static struct expanded_key __encrypt_key;

void setkey(const char *key)
{
	unsigned char bkey[8];
	int i, j;

	for (i = 0; i < 8; i++) {
		bkey[i] = 0;
		for (j = 7; j >= 0; j--, key++)
			bkey[i] |= (uint32_t)(*key & 1) << j;
	}

	__des_setkey(bkey, &__encrypt_key);
}

void encrypt(char *block, int edflag)
{
	struct expanded_key decrypt_key, *key;
	uint32_t b[2];
	int i, j;
	char *p;

	p = block;
	for (i = 0; i < 2; i++) {
		b[i] = 0;
		for (j = 31; j >= 0; j--, p++)
			b[i] |= (uint32_t)(*p & 1) << j;
	}

	key = &__encrypt_key;
	if (edflag) {
		key = &decrypt_key;
		for (i = 0; i < 16; i++) {
			decrypt_key.l[i] = __encrypt_key.l[15-i];
			decrypt_key.r[i] = __encrypt_key.r[15-i];
		}
	}

	__do_des(b[0], b[1], b, b + 1, 1, 0, key);

	p = block;
	for (i = 0; i < 2; i++)
		for (j = 31; j >= 0; j--)
			*p++ = b[i]>>j & 1;
}