https://github.com/konstantinullrich/hashcash

A hashcash proof of work implementation for Dart and Flutter
https://github.com/konstantinullrich/hashcash

dart-package dartlang flutter flutter-package hashcash proof-of-work

Last synced: about 1 month ago
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A hashcash proof of work implementation for Dart and Flutter

• Host: GitHub
• URL: https://github.com/konstantinullrich/hashcash
• Owner: konstantinullrich
• License: mit
• Created: 2020-01-22T09:49:55.000Z (almost 5 years ago)
• Default Branch: trunk
• Last Pushed: 2023-12-09T09:56:18.000Z (11 months ago)
• Last Synced: 2024-09-28T16:20:41.560Z (about 2 months ago)
• Topics: dart-package, dartlang, flutter, flutter-package, hashcash, proof-of-work
• Language: Dart
• Homepage: https://pub.dev/packages/hashcash_dart
• Size: 30.3 KB
• Stars: 3
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# Hashcash

Hashcash is a proof-of-work algorithm, which has been used as a denial-of-service counter measure technique in a 

number of systems.

A hashcash stamp constitutes a proof-of-work which takes a parameterizable amount of work to compute for the sender. 

The recipient (and indeed anyone as it is publicly auditable) can verify received hashcash stamps efficiently. 

Hashcash was invented by [Adam Back][cypherspace] in [1997][papers]

At this point it is most widely used as the [bitcoin][bitcoin] mining function.

The email anti-spam tool, like the proof-of-work algorithm, is also called hashcash and is used to create stamps to 

attach to mail to add a micro-cost to sending mail to deter spamming. The main use of the hashcash stamp is as a 

white-listing hint to help hashcash users avoid losing email due to content based and blacklist based anti-spam systems.

Hashcash source code includes a library form, and also the algorithm is extremely simple to code from scratch with the 

availability of a hash library. Verification can be done by a human eye (count leading 0s) even with availability of 

common preinstalled command line tools such as sha1sum. The algorithm works with a cryptographic hash, such as SHA1, 

SHA256 or coming SHA3 that exhibits 2nd-preimage resistance. Note that 2nd-preimage resistance is a stronger hash 

property than the collision resistance property.

## Usage

A simple example:

```dart

import 'package:hashcash/hashcash_dart.dart';

main() {

  var stamp = Hashcash.mint('[email protected]');

  var checked = Hashcash.check(stamp, resource: '[email protected]');

}

```

## Features and bugs

Please file feature requests and bugs at the [issue tracker][tracker].

[cypherspace]: http://www.cypherspace.org/adam/

[papers]: http://hashcash.org/papers/

[bitcoin]: https://bitcoin.it/

[tracker]: https://github.com/konstantinullrich/hashcash/issues