Subversion Repositories planix.SVN

/*
 *      Data Encryption Standard
 *      D.P.Mitchell  83/06/08.
 *
 *      block_cipher(key, block, decrypting)
 *
 *      these routines use the non-standard 7 byte format
 *      for DES keys.
 */
#include <u.h>
#include <libc.h>
#include <auth.h>
#include <libsec.h>

/*
 * destructively encrypt the buffer, which
 * must be at least 8 characters long.
 */
int
encrypt(void *key, void *vbuf, int n)
{
        ulong ekey[32];
        uchar *buf;
        int i, r;

        if(n < 8)
                return 0;
        key_setup(key, ekey);
        buf = vbuf;
        n--;
        r = n % 7;
        n /= 7;
        for(i = 0; i < n; i++){
                block_cipher(ekey, buf, 0);
                buf += 7;
        }
        if(r)
                block_cipher(ekey, buf - 7 + r, 0);
        return 1;
}

/*
 * destructively decrypt the buffer, which
 * must be at least 8 characters long.
 */
int
decrypt(void *key, void *vbuf, int n)
{
        ulong ekey[128];
        uchar *buf;
        int i, r;

        if(n < 8)
                return 0;
        key_setup(key, ekey);
        buf = vbuf;
        n--;
        r = n % 7;
        n /= 7;
        buf += n * 7;
        if(r)
                block_cipher(ekey, buf - 7 + r, 1);
        for(i = 0; i < n; i++){
                buf -= 7;
                block_cipher(ekey, buf, 1);
        }
        return 1;
}