NAME

       Mail::SpamAssassin::Plugin::Hashcash - perform hashcash verification tests

SYNOPSIS

         loadplugin     Mail::SpamAssassin::Plugin::Hashcash

DESCRIPTION

       Hashcash is a payment system for email where CPU cycles used as the basis for an e-cash system.  This
       plugin makes it possible to use valid hashcash tokens added by mail programs as a bonus for messages.

USER SETTINGS

       use_hashcash { 1 | 0 }   (default: 1)
           Whether to use hashcash, if it is available.

       hashcash_accept user@example.com ...
           Used to specify addresses that we accept HashCash tokens for.  You should set it to match all the
           addresses that you may receive mail at.

           Like whitelist and blacklist entries, the addresses are file-glob-style patterns, so
           "friend@somewhere.com", "*@isp.com", or "*.domain.net" will all work.  Specifically, "*" and "?" are
           allowed, but all other metacharacters are not.  Regular expressions are not used for security
           reasons.

           The sequence %u is replaced with the current user's username, which is useful for ISPs or multi-user
           domains.

           Multiple addresses per line, separated by spaces, is OK.  Multiple "hashcash_accept" lines is also
           OK.

       hashcash_doublespend_path /path/to/file   (default: ~/.spamassassin/hashcash_seen)
           Path for HashCash double-spend database.  HashCash tokens are only usable once, so their use is
           tracked in this database to avoid providing a loophole.

           By default, each user has their own, in their "~/.spamassassin" directory with mode 0700/0600.  Note
           that once a token is 'spent' it is written to this file, and double-spending of a hashcash token
           makes it invalid, so this is not suitable for sharing between multiple users.

       hashcash_doublespend_file_mode            (default: 0700)
           The file mode bits used for the HashCash double-spend database file.

           Make sure you specify this using the 'x' mode bits set, as it may also be used to create directories.
           However, if a file is created, the resulting file will not have any execute bits set (the umask is
           set to 111).