Is the encrypted password's salt simply random?

[F. L. Charles Seeger III]

In article <1991Feb27.202424.16444 at rigel.econ.uga.edu> glenn at rigel.econ.uga.edu (Glenn F. Leavell) summarizes:
|In article <1991Feb26.201846.22584 at rigel.econ.uga.edu> I recently wrote:
|>I'm using a randomly generated two-character salt from the set [a-zA-Z0-9./],
|>and everything seems to be working fine.  Here's my question:  is this
|>the right way to choose the salt - just a random thing?

Included as part of the summary:

| >The old BSD 4.3 "passwd" program uses 
| >    (void)time(&salt);
| >    salt = 9 * getpid();
| >    saltc[0] = salt & 077;
| >    saltc[1] = (salt>>6) & 077;
| >    for (i = 0; i < 2; i++) {
| >        c = saltc[i] + '.';
| >        if (c > '9')
| >            c += 7;
| >        if (c > 'Z')
| >            c += 6;
| >        saltc[i] = c;
| >    }
| >    return(crypt(pwbuf, saltc));
| >which is based on the time of day clock.

Note that the salt generated by this code does not depend on the time.  The
assignment in the second line discards the result of the time() call.  The
fix that I have seen suggest is to change the assignment operator from "="
to "+=".  However, the UCB folks seem to have changed the code more
drastically.

static char sccsid[] = "@(#)passwd.c    4.42 (Berkeley) 6/19/90";
...
char *
getnewpasswd(pw, temp)
        register struct passwd *pw;
        char *temp;
{
        register char *p, *t;
        char buf[_PASSWORD_LEN+1], salt[2], *crypt(), *getpass();
...
        /* grab a random printable character that isn't a colon */
        (void)srandom((int)time((time_t *)NULL));
#ifdef NEWSALT
        salt[0] = '_';
        to64(&salt[1], (long)(29*25), 4);
        to64(&salt[5], (long)random(), 4);
#else
        to64(&salt[0], (long)random(), 2);
#endif
        return(crypt(buf, salt));
}

Personally, I'm a bit suspicious of NEWSALT and the "&salt[5]".

Chuck
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