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).