Hkdf

Welcome to your new gem! In this directory, you'll find the files you need to be able to package up your Ruby library into a gem. Put your Ruby code in the file lib/hkdf. To experiment with that code, run bin/console for an interactive prompt.

TODO: Delete this and the text above, and describe your gem

Installation

Add this line to your application's Gemfile:

gem 'hkdf', github: 'Yamaguchi/hkdf/'

And then execute:

$ bundle

Or install it yourself as:

$ gem install specific_install
$ gem specific_install -l 'https://github.com/Yamaguchi/hkdf.git'

Usage

Use OpenSSL implementation

Specify 'hash' option ("sha256", "sha384", "sha512", "ripemd", ...)

root@5cd510b346b2:~/hkdf# ./bin/console
irb(main):001:0> ikm = ["0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b"].pack("H*")
=> "\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v"
irb(main):002:0> salt = ["000102030405060708090a0b0c"].pack("H*")
=> "\x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f"
irb(main):003:0> info = ["f0f1f2f3f4f5f6f7f8f9"].pack("H*")
=> "\xF0\xF1\xF2\xF3\xF4\xF5\xF6\xF7\xF8\xF9"
irb(main):004:0> length = 42
=> 42
irb(main):005:0> Hkdf.hkdf(ikm, salt: salt, info: info, length: length, hash: "sha256", hash_len: 32)
=> "<\xB2_%\xFA\xAC\xD5z\x90COd\xD06/*--\n\x90\xCF\x1AZL]\xB0-V\xEC\xC4\xC5\xBF4\x00r\b\xD5\xB8\x87\x18Xe"

Use Custom HMAC function

You can use any hmac function (such as blake2b...), instead of functions supported by openssl. Example of black2b is following(using rbnacl and ruby_hmac library):

require "rbnacl"
require "ruby_hmac"

class Blake2bHMAC < HMAC::Base
  def initialize(key = nil)
    super(RbNaCl::Hash::Blake2b, 128, 64, key)
  end
  public_class_method :new, :digest, :hexdigest
end

root@5cd510b346b2:~/hkdf# ./bin/console
irb(main):003:0> ikm = ["0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b"].pack("H*")
=> "\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v\v"
irb(main):004:0> salt = ["000102030405060708090a0b0c"].pack("H*")
=> "\x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f"
irb(main):005:0> info = ["f0f1f2f3f4f5f6f7f8f9"].pack("H*")
=> "\xF0\xF1\xF2\xF3\xF4\xF5\xF6\xF7\xF8\xF9"
irb(main):006:0> length = 42
=> 42
irb(main):007:0>  Hkdf.hkdf(ikm, salt: salt, info: info, length: length) { |key, data| Blake2bHMAC.new(key).update(data).digest }
=> "\x88\x15\xE1\xA8[^\x90\xE6\x17C#\xFD\xD1\x80$\x88\x87\xA7\x13\x8A\xF6\xDC\\\x83 \xFD\xE2\x1A`\xA0x\x80\x82g\xD6\xA4\ej\x93\x8D{0"

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 at https://github.com/Yamaguchi/hkdf. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

Code of Conduct

Everyone interacting in the Hkdf project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.