Chainpoint

A client for creating and verifying Chainpoint proofs.

Installation

Add this line to your application's Gemfile:

gem 'chainpoint'

And then execute:

$ bundle

Or install it yourself as:

$ gem install chainpoint

Usage

Initialize new hash object

sha256 = '09ca7e4eaa6e8ae9c7d261167129184883644d07dfba7cbfbc4c8a2e08360d5b'
chainpoint_hash = ChainPoint::Hash.new(sha256)

Chainpoint::Hash.from_data is a convenience method to create a new Chainpoint::Hash from raw data:

chainpoint_hash = Chainpoint::Hash.from_data('hello, world')
# => #<Chainpoint::Hash @hash="09ca7e4eaa6e8ae9c7d26116712918...>

Submit Hash

Use this function to submit a hash, and receive back the proof handles needed to later retrieve a proof.

By default hashes are submitted to three Nodes to help ensure a proof will become available at the appropriate time. Only one such proof need be permanently stored, the others provide redundancy.

chainpoint_hash = Chainpoint::Hash.from_data('hello, world')
proof_handles = chainpoint_hash.submit
# =>
[
  {
    'hash_id_node' => '1d1aa8a0-8f42-11e8-967f-01a68adfc010',
    'uri' => 'http://45.77.197.76'
  }
  ...
]

Get Proof

Once a hash has been submitted, it contains proof handles that can be used to retrieve the proof. It's likely that you will be retrieving proofs at a later time, so it is possible to initialize a Chainpoint::Hash object with proof handle data returned from a previous submit.

A Chainpoint::Proof representing the first valid proof will be returned, or nil if there is no valid proof.

chainpoint_hash = Chainpoint::Hash.new(sha256, proof_handles: proof_handles)
chainpoint_hash.proof

#=> #<Chainpoint::Proof @proof="eJyNk71uFDEx0=...", @hash_id_node="1672f730-...1", @anchors_complete=["cal"]>

You may also pass an anchor type to return only proofs matching that type. By default chainpoint anchors to a Calendar blockchain (cal) which usually completes in about 10s and to the Bitcoin blockchain btc which usually completes in about 2h.

proof = Chainpoint::Hash.new(sha256, proof_handles: proof_handles).proof('btc')
#=> #<Chainpoint::Proof @proof="eJyNk71uFDEx0=...", @hash_id_node="1672f730-...1", @anchors_complete=["cal", "btc"]>

Decode a Proof

A Chainpoint::Proof object contains a binary representation of the proof can be converted to JSON to view the Chainpoint JSON Schema:

proof.decode
# =>

Verify a Proof

You can verify a proof against each of the blockchains the proof has been anchored to:

proof.verify

Response

{
  "proof_index" => 0,
  "hash" => "09ca7e4eaa6e8ae9c7d261167129184883644d07dfba7cbfbc4c8a2e08360d5b",
  "hash_id_node" => "1672f730-536b-11e9-9241-015d8fee1e71",
  "hash_submitted_node_at" => "2019-03-31T04:11:41Z",
  "hash_id_core" => "18456d40-536b-11e9-8c0f-016fe824db22",
  "hash_submitted_core_at" => "2019-03-31T04:11:44Z",
  "anchors" => [
    {
      "branch" => "cal_anchor_branch",
      "type" => "cal",
      "valid" => true,
      "block_id" => "2967333", "block_value" => "74e2b62f68463f53105b65d57c729e5488b7833d6ebb259561b84e43d826c7ea"
    }
  ],
  "status"=>"verified"
}

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub chainpoint.

Other

PHP Composer Package and its GitHub Repository.

KenjiOhtsuka / chainpoint_gem