NAME

SYNOPSIS

    # Create a PAR archive containing an encrypted Perl script:
    $ pp -f Crypto -M Filter::Crypto::Decrypt -o hello hello.pl

    # The same, but with included modules encrypted as well:
    $ pp -f Crypto -F Crypto -M Filter::Crypto::Decrypt -o hello hello.pl

    # Encrypt Perl source code in $code:
    use PAR::Filter::Crypto;
    PAR::Filter::Crypto->apply(\$code);

DESCRIPTION

The usual means of producing a PAR archive is using the pp script, which also comes with the PAR distribution. That script's -f and -F command-line options can be used to specify a "filter" through which to pass the Perl files being put into the PAR archive. Specifying this sub-class as the filter (i.e. "-f Crypto" for scripts and/or "-F Crypto" for modules) means that the Perl files will be encrypted using the Filter::Crypto::CryptFile module. The resulting encrypted files are what will be placed in the PAR archive.

Note that the encrypted script requires the Filter::Crypto::Decrypt module in order to decrypt itself when it is run. The original Perl script will not have specified any such dependency, so pp will not automatically include that module in the PAR archive for you. Therefore, you must use the -M option to force that module to be included. Also note that if you use the -F option to encrypt modules as well then the filtering will automatically skip the Filter::Crypto::Decrypt module itself for obvious reasons. A typical pp invocation is thus something like:

    $ pp -f Crypto -F Crypto -M Filter::Crypto::Decrypt -o hello hello.pl

(Version 0.75 of the Module::ScanDeps module, used by pp to scan for dependencies that need including in the PAR archive, is known to have problems finding shared library files for modules specified by pp's -M option (as illustrated above). If you find that the shared library file for Filter::Crypto::Decrypt is missing from your PAR archive then you need to upgrade Module::ScanDeps to version 0.76 or higher.)

Of course, you must not include the Filter::Crypto::CryptFile module as well, otherwise people to whom you distribute your PAR archive will have the means to easily decrypt the encrypted Perl script within it!

Also, note that the script is encrypted by reading its entire contents into memory, encrypting it in memory, and then writing it out to disk. This should be safe for most purposes given that Perl scripts are typically not very large, but other methods should be considered instead if this is likely to cause out-of-memory errors due to the size of the scripts, e.g. if the scripts have very large "__DATA__" sections.

DIAGNOSTICS

    (W) A warning (optional).
    (F) A fatal error (trappable).
    (I) An internal error that you should never see (trappable).

EXPORTS

KNOWN BUGS

SEE ALSO

Filter::Crypto.

ACKNOWLEDGEMENTS

AUTHOR

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VERSION

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HISTORY