Aside from the packet sniffing attack, what you are doing is very vulnerable to a dictionary attack.

You could mitigate this risk significantly by using a random salt instead of the constant "01".

Basically, if anyone finds out that the salt is "01", they only have to make one pass to encrypt every word in a dictionary and guess passwords. Randomize the salt, and they have to make a lot more passes.

One way to do that:

my @chars=(a..z,A..Z,0..9,'.','/');
my $salt= $chars[rand(@chars)] . $chars[rand(@chars)];

[download]
Update: Another option would be to use Crypt::PasswdMD5, which has the same basic interface as good old crypt, but it supposed to be more resistant to dictionary attacks. (YMMV, I'm not a cryptographer)

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

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