an application that i'm maintaining originally used Crypt:DES to 'encrypt' passwords for storage in a cookie to maintain a logged-in user. the app has decided to break with passwords longer than 8 bytes ( which i found out is a limitation of Crypt::DES -- it only handles 8-byte data ).

today I'm working on replacing the Crypt::DES with Crypt::CBC to allow for arbitrary-length password strings, but I can't get validation/ verification of the passwords from the cookie.

in the set_cookie routine: 


        my $cipher = Crypt::CBC->new(
                 {'key'             => 'stringie',
                  'cipher'          => 'DES',
                  'iv'              => 'vectory!',
                  'regenerate_key'  => 0,   # default true
                  'padding'         => 'space',
                  'prepend_iv'      => 1
                  } );

        my $epassword = $cipher->encrypt_hex($password);

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and the new $epassword is tossed into the cookie.

and later ( on subsequent hits to the app, essentially) we check the cookie pass against the DB pass like so: 

        my $cipher = Crypt::CBC->new(
                 {'key'             => 'stringie',
                  'cipher'          => 'DES',
                  'iv'              => 'vectory!',
                  'regenerate_key'  => 0,   # default true
                  'padding'         => 'space',
                  'prepend_iv'      => 1
                  } );

        my $dbpwmd5 = $cipher->encrypt_hex($dbpw);

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where  $dbpw is just fetched from the DB based on the username ....

and the values don't match. the newly encrypted $dbpw and the value from the cookie, that is.

after reading a couple other nodes ( Crypt::CBC question, Safe symmetric encryption - Crypt::CBC + Crypt::Blowfish? ) a block cipher (like DES) should allow for comparision.

In reply to Crypt::CBC and verifying passwords by geektron

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