cryptPLAINTEXT,SALT
This function encrypts a string exactly in the manner of crypt (3). This is useful for checking the password file for lousy passwords.[ 2 ] Only the guys wearing white hats are allowed to do this.
[2] What you really want to do is prevent people from adding the bad passwords in the first place.
To see whether a typed-in password
$guess
matches the password
$pass
obtained from a file
(such as
/etc/passwd
),
try something like the following:
if (crypt($guess, $pass) eq $pass) {
# guess is correct
}
Note that there is no easy way to decrypt an encrypted password apart from guessing. Also, truncating the salt to two characters is a waste of CPU time, although the manpage for crypt (3) would have you believe otherwise.
Here's an example that makes sure that whoever runs this program knows their own password:
$pwd = (getpwuid ($<))[1];
$salt = substr $pwd, 0, 2;
system "stty -echo";
print "Password: ";
chop($word = <STDIN>);
print "\n";
system "stty echo";
if (crypt($word, $salt) ne $pwd) {
die "Sorry...\n";
} else {
print "ok\n";
}
Of course, typing in your own password to whoever asks for it is unwise.
The crypt function is unsuitable for encrypting large quantities of data. Find a library module for PGP (or something like that) for something like that.
[ Library Home | Perl in a Nutshell | Learning Perl | Learning Perl on Win32 | Programming Perl | Advanced Perl Programming | Perl Cookbook ]