Publisher Bucks

Is there any reason that I shouldnt put this in a .php script to allow a client to download a digital file they have purchased?

define('PROTECTED_USERNAME', 'username');
define('PROTECTED_PASSWORD', 'password');

This is to let a client download a file in a .htpasswd protected directory.

The download link is already limited to 30 minutes and before the links are given they have to enter a transaction id and their first and last name.

Any security issue is what I'm mainly concerned about.

Thanks.

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