[Cryptography] [ANNOUNCE] HashCash Digital Cash

Ashish Gulhati crypto at ashish.neomailbox.com
Wed Jun 21 02:06:56 EDT 2017

An untraceable, permissionless digital cash system based on blind

Screenshots, FAQ, and executables for some platforms are at:

HashCash is free software, written in Perl and published under the
Artistic License 2.0.

Source can be downloaded from CPAN. On Unix-ish systems it should also
be possible to download and install the package with:

   cpan Crypt::HashCash

(note different capitalization from Adam's Hashcash)

HashCash is a lightweight Chaumian blind-signature based digital cash 
system, designed to work without the need for user registration or accounts.

The current implementation is a minimal usable version. It is experimental 
and released for beta testing.

HashCash can operate with various blind signature algorithms and value
bases. The initial version includes support for blind RSA and ECDSA
signatures, and a vault based on Bitcoin.

HashCash coins are bearer tokens of specific denominations,
blind-signed by a vault, representing a quantity of some value
(precious metals / Bitcoin / altcoins / fiat / whatever) stored by the

Users can export coins from their wallets and send them directly to
anyone else using any communication medium. Coins can be encrypted
when exported, and the encryption passphrase sent to the recipient
using an alternate communication method, to protect coins in
transit. For in-person transactions, recipients can just scan coins as
QR codes from payers' devices.

The wallet can work with multiple independent vaults, just as an email
client might connect to multiple email accounts on different servers.

With the free vault software and fairly modest hardware and bandwidth
requirements, operating a HashCash vault is within the capabilities of
most people with basic computer skills, facilitating decentralizaton
based on a diversity of competing private vaults. Independent
automated reliability and reputation tracking of vaults could help
users select reliable vaults to use.

Coin minting and verification fees can be set independently by each
vault, and are built into each interaction with a vault, which enables
vaults to operate without the need for user accounts.

A vault's private keys can be kept completely offline at all times, by
running the vault on machines air-gapped from the Internet and
communicating with them over serial links. The HashCash protocol is
designed to facilitate air-gapped vaults, as well as completely
offline yet fully functional wallets, which can provide a high level
of security for naive users.

Offline mode for the wallet is included in current implementation. I'm
still fine-tuning the support for air-gapped vaults. It works and has 
been well tested, just needs to be cleaned up. Support for air-gapped 
vaults should be included in an upcoming release soon, and an 
experimental live air-gapped vault should also be online shortly. In 
the meantime, you can get a feel for the system by running a vault 
locally. More details on that on the Download page:


Comments, bug reports, code, translation assistance, etc. most welcome
and greatly appreciated.



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