Filter::decrypt - template for a decrypt source filter
use Filter::decrypt ;
This is a sample decrypting source filter.
Although this is a fully functional source filter and it does implement a very simple decrypt algorithm, it is not intended to be used as it is supplied. Consider it to be a template which you can combine with a proper decryption algorithm to develop your own decryption filter.
It is important to note that a decryption filter can never provide complete security against attack. At some point the parser within Perl needs to be able to scan the original decrypted source. That means that at some stage fragments of the source will exist in a memory buffer.
The best you can hope to achieve by decrypting your Perl source using a source filter is to make it impractical to crack.
Given that proviso, there are a number of things you can do to make life more difficult for the prospective cracker.
If you feel that the source filtering mechanism is not secure enough you could try using the unexec/undump method. See the Perl FAQ for further details.
19th December 1995