Notice the first line of the documentation?

"Crypt::CBC compliant Rijndael encryption module"

That should tell you something!

use Crypt::CBC;
my $key = "a" x 32;
my $cipher = Crypt::CBC->new( -cipher => 'Rijndael', -key => $key );
my $ciphertext = $cipher->encrypt($plaintext);
[download]

use Crypt::CBC;
my $key = "a" x 32;
my $cipher = Crypt::CBC->new( -cipher => 'Rijndael', -key => $key );
my $plaintext  = $cipher->decrypt($ciphertext);
[download]

It handles padding, for you.
It handles salting for you.
It handles chaining for you.

And make sure your database field is large enough.