About:
HashCash is an anti-spam, anti-DoS system for email. The concept centers around the sender of the mail completing a computationally expensive task (in this case, generating hash collisions) that the recipient can verify very quickly. This allows the sender to "pay" for transport in CPU cycles, creating artificial scarcity. Programs are included to add payment to messages (for the sender) and to verify message payment (for the recipient).

Author:
Adam Back <adam (at) cypherspace (dot) org> [contact developer]

Rating:	reset 1 2 3 4 5 6 7 8 9 10
8.23/10.00 (1 vote)

Homepage:
http://www.hashcash.org/
Tar/GZ:
http://www.hashcash.org/source/hashcash-1.09.tgz
Changelog:
http://www.hashcash.org/binaries/rpms/hashcash-1.09-1.i386.rpm
RPM package:
http://www.hashcash.org/binaries/rpms/hashcash-1.09-1.src.rpm
OS X package:
http://fink.sourceforge.net/pdb/package.php/hashcash
BSD Ports URL:
ftp://ftp.freebsd.org/[..]reeBSD/ports/distfiles/hashcash-1.02.tgz

Trove categories: [change]

[Development Status]		6 - Mature
[Intended Audience]		End Users/Desktop
[License]		Public Domain
[Operating System]		MacOS X, Microsoft, POSIX, POSIX :: BSD, POSIX :: Linux, Unix
[Topic]		Communications :: Email, Communications :: Email :: Mail Transport Agents, Other/Nonlisted Topic, Security, Utilities

Dependencies: [change]
No dependencies filed

 Branches

Branch	Version	Last release	License	URLs
Default	1.09	01-Oct-2004	Public Domain

 Articles referencing this project

• Debian: New hashcash packages fix arbitrary code execution
  by Patrick Lenz , in Security
  Wed, Jul 26th 2006 14:17
  

 Comments

[»] spam assassin 3.0
by Adam Back - Oct 1st 2004 17:12:45

spam assassin 3.0 supports hashcash could still really use hashcash support for mozilla mail (thunderbird/mozilla mail). See: for the tracking bug info

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[»] Good idea....
by Samuel Liddicott - Oct 1st 2004 02:46:43

and will thus require all "owned" machines to be upgraded with new spamming software than can compute these hashes. Maybe owners will wonder why their PC's are slowing down.

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