Ok this is how I did it. Note I'm very new to perl programming so this probably isn't the best way.
Assuming you have authenticated the user (from a database or text file or where-ever), and $user is the user's id

use MD5 ;
    
my $md5 = new MD5 ;
$md5->reset ;

my $yday = (localtime)[7];

# create certificate / session id
my $certif = $user . $yday .  "do4k.g0" . $ENV{'HTTP_USER_AGENT'}  .  
+$ENV{'REMOTE_ADDR'} ;

# encrypt certificate
$md5->add($certif);
my $enc_cert = $md5->hexdigest() ;

# set cookie
print "Set-Cookie: SESSION=$enc_cert; path=/\n" ;
print "Set-Cookie: NAME=$user; path=/\n"  ;

# and continue
print "Content-type: text/html\n\n"  ;
print "Your logged In!"  ;

[download]
Then everytime the script is called get the certificate out the cookie and recreate a certificate and compare the two. 
#  $session and $user came from cookie
use MD5 ;
    
my $md5 = new MD5 ;
$md5->reset ;

#create ceritficate
my $yday = (localtime)[7];
my $certif = $username . $yday . do4k.g0 . $ENV{'HTTP_USER_AGENT'}  . 
+ $ENV{'REMOTE_ADDR'}  ;

# encrypt Certificate
$md5->add($certif);
my $enc_cert = $md5->hexdigest() ;

#compare
if($enc_cert eq $session) {
   # we're logged in - run script ;
} else {
   # we're not logged in - disp error msg
}

[download]
And a logout can simply be done with a 
print<<"END" ;
Set-Cookie: SESSION=; path=\
Set-Cookie: NAME=; path=\
Content-type: text/html

Your logged out now
END

[download]
It would probably be wise to set expiration times for the cookies. Using the $yday means each certificate will expire at midnight which could be a problem.

Anyway I hope this helps
Nomis52

In reply to Re: Re: Re: Is this use of crypt() appropriate? by Nomis52
in thread Is this use of crypt() appropriate? by Anonymous Monk

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