hashchain 0.8.3

Helper to certify database entries, using hashchains and blockchains

Hashchain

Introduction

hashchain is a Python package developed to join the ease of use of Python with the security of blockchain to certify that your important records haven't been tampered with.

The core module creates a hash chain, attesting that no record can be tempered with, once saved. The blockchain module save a proof of your hashchain permanentely in the most secured way. Then, it's impossible to alter the haschain without causing a discrepancy with the blockchain.

No need for third party certification anymore. No more single point of failure nor certification costs.

Disclaimer

The package is still 'work in progress' Do not use it before the official beta release. All the features are still subject to changes without any advertisement and can broke previously running scripts

Installation

This python package is available on PyPi package manager. I recommend installing it in a virtual environment.

1. Open a terminal and run the following command : pip install hashchain
2. Import the package in you script with import hashchain

This package is tested against Python 3.5.7 and 3.7.1 versions

How to start using haschain?

The documentation lives on ReadTheDocs

Contribute

I would be happy to hear from you if you have any comments, suggestions or requests to share with me.

Changelog

0.8.3

Changes:

• Update the Ethereum Smart Contract contract to remove unused functions.

0.8.2

Fixes:

• Update the Record object to sort the content in an ordered dict to fix python 3.5 compatibility issue. /!\ This breaks previous versions as this impact the hash calculation.

0.8.1

Fixes:

• Remove a hashlib reference in ethereum.contract

0.8.0

Changes:

• Updated the hash algorythm to Keccak (sha3_256). /!\ This breaks previous versions.
• Added Python 3.5 and 3.6 compatibility

0.7.0

Changes:

• Removed every json conversion from the records module. /!\ This breaks previous versions. The hash calculation was impacted by this change.

0.6.2

Fixes:

• Updated the Ethereum contract to comply with MythX security standards

0.6.0

Features:

• Add wait argument to ethereum.EthConnector().record() to wait until the transaction receipt is received. This avoid sending many transactions with the same nonce, while running this function in a loop.

0.5.0

Features:

• Updated the Ethereum Smart contract to store a byte32=>byte32 key pair instead of int64=>byte32
• Updated ethereum.EthContract().record() and ethereum.EthContract().record() to take a string as key input instead of an int. The string is hashed and the hash is used as key on the blockchain.

0.4.2

Fixes:

• Removed the contract JSON file fron the structure and added ethereum/contract_interface to get the contract abi and binary.

0.4.1

Fixes:

• Included the ethereum module in the package

0.4.0

Features:

• Add more precise feedback on Record.verify() errors
• Add ethereum.EthContract() to enable deploying the solidity smart contract on the Ethereum blockchain

0.3.0

Features:

Request.to_dict() and .to_json() now returns a simple object. The keys "hash" and "previous_hash" are appended at the same level

Fix:

Add web3.py to the install_requires list

0.2.0

Features:

• Add records to build hash chains
• Add ethereum_connector to store hashes on the Ethereum blockchain

0.1.0

First Alpha release.