This package was debianized by Hubert Chan on Sat, 27 Dec 2003 15:23:30 -0500. It was downloaded from http://www.hashcash.org/ Copyright Holder: Adam Back License: The source contains getopt.c and getopt.h, which are copyright by the FSF, and licensed under the GPL. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA On Debian systems, the full text of the GPL can be found at /usr/share/common-licenses/GPL. The source contains fip180-1.txt, written by the United States government, and is in the public domain. The hashcash-sendmail and hashcash-request programs in the examples directory are copyright Kyle Hasselbacher, and licensed under the GPL. The hashfork.py program in the examples directory was written by Hubert Chan, and is in the public domain. The rest of the software is licensed under your choice of (in the upstream author's preference): - Cypherpunks CPL (Cypherpunks anti-License) - public domain - modified BSD (without advertising clause) - LGPL 2.1 - GPL 2 The text of the Cypherpunks CPL is included below. On Debian systems, the BSD license can be found at /usr/share/common-licenses/BSD, the LGPL at /usr/share/common-licenses/LGPL, and the GPL at /usr/share/common-licenses/GPL. The upstream author makes the following comments and requests. They are not licensing requirements: - If you have to make changes to make this library work for your system or application it would be useful if you could tell me what you had to do, and optionally send me the source changes so I can include them or update the library. The aim is to make a practically useful library. - It would be useful if you could inform me if you use or distribute hashcash. The intent here is to give me feedback and insight into the areas of application which people find useful in practice. - If you are unclear on how to use hashcash there is a FAQ here: http://www.hashcash.org/faq.html. If that doesn't answer your question or doesn't apply to your usage, feel free to discuss in email. - It may help the deployment of hashcash as an anti-spam system if different systems based on hashcash were interoperable as far as that makes sense for your system. To this end the FAQ http://www.hashcash.org/faq.html and Internet-Draft http://www.hashcash.org/draft-hashcash.txt document my thoughts in this area. See also the hashcash home page http://www.hashcash.org and paper there as I update with links to deployed systems which it might be useful for you to interoperate with. Cypherpunks anti-License Intent The intent of the Cypherpunks anti-License (CPL) is to inform users that they are free to use and redistribute the indicated work or any derived or modified work in any manner they choose. Works distributed under the CPL are in the Public Domain. Licensing The CPL is not a license, it does not require the user to do or not do anything; the user does not agree to any terms, because there are no terms, and the user does not need to do anything to indicate acceptance or rejection of the CPL. Non Litigation The CPL serves to pledge to the user that the distributors will behave in a manner consistent with the non-existance of Intellectual Property (IP) laws as far as they are able. The distributors will not use or participate as far as they are able to government legal systems to attempt to enforce requests restricting the use, modifications, or redistribution of the work for perpetuity. The distributor may prefer to be anonymous to preclude attempts to coerce them into enforcing IP laws relating to this work against their will. Requests The work may be distributed with some distributor requests in addition to the CPL. The distributor pledges similarly to not attempt to use IP laws to enforce these requests. Redistribution Users choosing to redistribute this work may change anything about the work, including distributing it under a different license, and adding or removing previous distributors requests. Interpretation The CPL is completely liberal. Here are some examples of implications of this which are not true for many licenses. The user can redistribute the work or a derived or modified work * under a different license of their choosing * with or without source code as they choose * without acknowledging the distributors or authors * with false or innaccurate claims about authorship of the work * advertise without acknowledging the authors Requests can be arbitrary, but are requests only. Example of requests that the distributor may choose to make: * that improvements to the work be drawn to the distributors attention * that improvements to the work be released back to the distributor under the CPL * that the distributors name not be used to advertise derived works without the distributors approval Legacy Considerations The distributor may choose to inform the user of his opinion of the IP status of the work, for example by identifying any IP law restricted aspects such as the copyright holders of parts or the whole of the work, trademark owners of trademarks used in the work, potentially applicable patents on algorithms or ideas contained in the work, but the distributor is not obliged to do so and takes no responsibility for the accuracy of such information. Background The CPL is written from a mindset which derides the very concept of Intellectual Property restrictions as being incompatible with a free society. Cryptographically assured anonymity and anonymous use of Internet resources mean that denizens of cypherspace can ignore copyright, licenses attempting to control use and distribution of works, and patents on ideas. It is not possible to enforce IP laws by calls to government legal systems when the flaunter is strongly anonymous. The enforcement of IP law and anonymity are in direct conflict. To fully enforce IP laws, anonymity would have to be outlawed. Cypherpunks believe this would be a bad thing, because control of information imparts power, and anonymity gives individuals control over disclosure of information about themselves and their actions.