bequest

Bequest

There might be times when you (the bequestor) want to provide data to a third party (the bequestee) for a limited time and/or only on a specific machine. Bequest enables password, MAC address and expiry-based protection of data via a single, binary, encrypted license file.

Installation

Add this line to your application's Gemfile:

gem 'bequest'

And then execute:

$ bundle

Or install it yourself as:

$ gem install bequest

Usage

The bequestor would run:

Bequest::License.create('path/to/source/data', 'path/to/out/file', 
  :expires_at => Time.now + 1.year,
  :password => 'secret word or phrase',
  :mac_addr => 'bequestee:MAC:address:for:example')

Parameters:

1. Source data file - this is the secret data you want made securely available to the client, it can be plain text or binary
2. Out file - the license file that will be created

Options (at least ONE of :password or :mac_addr must be set):

• :expires_at - time as a Ruby Time object, no expiry if omitted or set to nil
• :password - this can be any word or phrase and will be prompted for (if set and not supplied as an option) when the license is loaded
• :mac_addr - if set this will be read from the local machine when the bequestee loads the license if not supplied as an option

The serialised, binary license file contains a main checksum and a body. The body is composed of:

• The encrypted expiry time
• Password and MAC address booleans
• The compressed, encrypted source data
• The initialisation vector

The main checksum is of the body as a joined array, before it was serialised in the license file. It is used to validate the integrity of the license file.

The client would run:

lic, data = Bequest::License.load('path/to/lic/file',
  :password => 'whatever', :mac_addr => 'whatever')

The password will be prompted for if set and :password not supplied. The first MAC address of the local machine will be used if set and :mac_addr not supplied. data will be set to nil if authentication fails or it has expired. lic will always be populated regardless of success and may be queried as follows:

lic.valid?             # => true or false
lic.expired?           # => true or false
lic.expires_at         # => Ruby Time object
lic.status             # => :ok, :expired, :unauthorized, or :tampered

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request