Class: CryptoconditionsRuby::Types::ThresholdSha256Fulfillment

Inherits:
BaseSha256Fulfillment show all
Defined in:
lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb

Direct Known Subclasses

InvertedThresholdSha256Fulfillment

Constant Summary collapse

TYPE_ID = 
2
FEATURE_BITMASK = 
0x09

Constants inherited from Fulfillment

Fulfillment::REGEX

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from BaseSha256Fulfillment

#generate_hash

Methods inherited from Fulfillment

#condition, #condition_binary, #condition_uri, from_binary, from_dict, from_uri, #generate_hash, #serialize_binary, #serialize_payload, #serialize_uri, #type_id

Methods included from Crypto::Helpers

#base64_add_padding, #base64_remove_padding, #ed25519_generate_key_pair

Constructor Details

#initialize(threshold = nil) ⇒ ThresholdSha256Fulfillment

Returns a new instance of ThresholdSha256Fulfillment.



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 13

def initialize(threshold = nil)
  if threshold && (!threshold.is_a?(Integer) || threshold < 1)
    raise StandardError, "Threshold must be a integer greater than zero, was: #{threshold}"
  end
  self.threshold = threshold
  self.subconditions = []
end

Instance Attribute Details

#bitmask ⇒ Object

Returns the value of attribute bitmask.



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 11

def bitmask
  @bitmask
end

#subconditions ⇒ Object

Returns the value of attribute subconditions.



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 11

def subconditions
  @subconditions
end

#threshold ⇒ Object

Returns the value of attribute threshold.



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 11

def threshold
  @threshold
end

Class Method Details

.calculate_smallest_valid_fulfillment_set(threshold, fulfillments, state = nil) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 258

def self.calculate_smallest_valid_fulfillment_set(threshold, fulfillments, state = nil)
  state ||= { 'index' => 0, 'size' => 0, 'set' => [] }

  if threshold <= 0
    { 'size' => state['size'], 'set' => state['set'] }
  elsif state['index'] < fulfillments.length
    next_fulfillment = fulfillments[state['index']]
    with_next = ThresholdSha256Fulfillment.calculate_smallest_valid_fulfillment_set(
      threshold - next_fulfillment['weight'].abs,
      fulfillments,
      'size' => state['size'] + next_fulfillment['size'],
      'index' => state['index'] + 1,
      'set' => state['set'] + [next_fulfillment['index']]
    )

    without_next = ThresholdSha256Fulfillment.calculate_smallest_valid_fulfillment_set(
      threshold,
      fulfillments,
      'size' => state['size'] + next_fulfillment['omit_size'],
      'index' => state['index'] + 1,
      'set' => state['set']
    )
    with_next['size'] < without_next['size'] ? with_next : without_next
  else
    { 'size' => Float::INFINITY }
  end
end

.calculate_worst_case_length(threshold, subconditions, index = 0) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 166

def self.calculate_worst_case_length(threshold, subconditions, index = 0)
  return 0 if threshold <= 0
  if index < subconditions.length
    next_condition = subconditions[index]

    [
      next_condition['size'] + ThresholdSha256Fulfillment.calculate_worst_case_length(
        threshold - next_condition['weight'].abs,
        subconditions,
        index + 1
      ),
      ThresholdSha256Fulfillment.calculate_worst_case_length(
        threshold,
        subconditions,
        index + 1
      )
    ].max
  else
    -Float::INFINITY
  end
end

.predict_subcondition_length(cond) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 147

def self.predict_subcondition_length(cond)
  return cond['body'].condition_binary.length if cond['type'] == FULFILLMENT

  cond['body'].serialize_binary.length
end

.predict_subfulfillment_length(cond) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 153

def self.predict_subfulfillment_length(cond)
  fulfillment_len = if cond['type'] == FULFILLMENT
                      cond['body'].condition.max_fulfillment_length
                    else
                      cond['body'].max_fulfillment_length
                    end

  predictor = Utils::Predictor.new
  predictor.write_uint16(nil)
  predictor.write_var_octet_string('0' * fulfillment_len)
  predictor.size
end

.sort_buffers(buffers) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 286

def self.sort_buffers(buffers)
  Duplicate.duplicate(buffers).sort_by { |item| [item.length, item] }
end

Instance Method Details

#add_subcondition(subcondition, weight = 1) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 21

def add_subcondition(subcondition, weight = 1)
  if subcondition.is_a?(String)
    subcondition = Condition.from_uri(subcondition)
  end
  unless subcondition.is_a?(Condition)
    raise TypeError, 'Subconditions must be URIs or objects of type Condition'
  end
  unless weight.is_a?(Integer) || weight < 1
    raise StandardError, "Invalid weight: #{weight}"
  end

  subconditions.push(
    'type' => CONDITION,
    'body' => subcondition,
    'weight' => weight
  )
end

#add_subcondition_uri(subcondition_uri) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 39

def add_subcondition_uri(subcondition_uri)
  unless subcondition_uri.is_a?(String)
    raise TypeError, "Subcondition must be provided as a URI string, was #{subcondition_uri}"
  end

  add_subcondition(Condition.from_uri(subcondition_uri))
end

#add_subfulfillment(subfulfillment, weight = 1) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 47

def add_subfulfillment(subfulfillment, weight = 1)
  if subfulfillment.is_a?(String)
    subfulfillment = Fulfillment.from_uri(subfulfillment)
  end
  unless subfulfillment.is_a?(Fulfillment)
    raise TypeError, 'Subfulfillments must be URIs or objects of type Fulfillment'
  end
  if !weight.is_a?(Integer) || weight < 0
    raise StandardError, "Invalid weight: #{weight}"
  end
  subconditions.push(
    'type' => FULFILLMENT,
    'body' => subfulfillment,
    'weight' => weight
  )
end

#add_subfulfillment_uri(subfulfillment_uri) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 64

def add_subfulfillment_uri(subfulfillment_uri)
  unless subfulfillment_uri.is_a?(String)
    raise TypeError, "Subfulfillment must be provided as a URI string, was: #{subfulfillment_uri}"
  end
  add_subfulfillment(Fulfillment.from_uri(subfulfillment_uri))
end

#calculate_max_fulfillment_length ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 112

def calculate_max_fulfillment_length
  total_condition_len = 0

  _subconditions = subconditions.map do |c|
    condition_len = ThresholdSha256Fulfillment.predict_subcondition_length(c)
    fulfillment_len = ThresholdSha256Fulfillment.predict_subfulfillment_length(c)
    total_condition_len += condition_len
    {
      'weight' => c['weight'],
      'size' => fulfillment_len - condition_len
    }
  end

  _subconditions.sort_by! { |x| x['weight'].abs }

  worst_case_fulfillments_length = total_condition_len + ThresholdSha256Fulfillment.calculate_worst_case_length(threshold, _subconditions)

  if worst_case_fulfillments_length == -Float::INFINITY
    raise StandardError, 'Insufficient subconditions/weights to meet the threshold'
  end

  # Calculate resulting total maximum fulfillment size
  predictor = Utils::Predictor.new
  predictor.write_uint32(threshold)
  predictor.write_var_uint(subconditions.length)
  subconditions.each do |c|
    predictor.write_uint8(nil)
    predictor.write_var_uint(c['weight']) unless c['weight'] == 1
  end

  predictor.skip(worst_case_fulfillments_length)

  predictor.size
end

#get_subcondition_from_vk(vk) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 79

def get_subcondition_from_vk(vk)
  subconditions.inject([]) do |store, c|
    if c['body'].is_a?(Ed25519Fulfillment) && Utils::Base58.encode(c['body'].public_key.to_s) == vk
      store.push(c)
    elsif c['body'].is_a?(ThresholdSha256Fulfillment)
      result = c['body'].get_subcondition_from_vk(vk)
      store += result if result
    end
    store
  end
end

#parse_dict(data) ⇒ Object

Raises:

  • (TypeError) 


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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 305

def parse_dict(data)
  raise TypeError, 'reader must be a dict instance' unless data.is_a?(Hash)
  self.threshold = data['threshold']

  data['subfulfillments'].each do |subfulfillments|
    weight = subfulfillments['weight']
    if subfulfillments['type'] == FULFILLMENT
      add_subfulfillment(Fulfillment.from_dict(subfulfillments), weight)
    elsif subfulfillments['type'] == CONDITION
      add_subcondition(Condition.from_dict(subfulfillments), weight)
    else
      raise TypeError, 'Subconditions must provide either subcondition or fulfillment.'
    end
  end
end

#parse_payload(reader, *args) ⇒ Object

Raises:

  • (TypeError) 


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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 188

def parse_payload(reader, *args)
  raise TypeError, 'reader must be a Reader instance' unless reader.is_a?(Utils::Reader)

  self.threshold = reader.read_var_uint
  condition_count = reader.read_var_uint

  condition_count.times do
    weight = reader.read_var_uint
    fulfillment = reader.read_var_octet_string
    condition = reader.read_var_octet_string
    if !fulfillment.empty? && !condition.empty?
      raise TypeError, 'Subconditions may not provide both subcondition and fulfillment.'
    elsif
      if !fulfillment.empty?
        add_subfulfillment(Fulfillment.from_binary(fulfillment), weight)
      elsif !condition.empty?
        add_subcondition(Condition.from_binary(condition), weight)
      else
        raise TypeError, 'Subconditions must provide either subcondition or fulfillment.'
      end
    end
  end
end

#to_dict ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 290

def to_dict
  subfulfillments = subconditions.map do |c|
    subcondition = c['body'].to_dict
    subcondition.merge!('weight' => c['weight'])
  end

  {
    'type' => 'fulfillment',
    'type_id' => type_id,
    'bitmask' => bitmask,
    'threshold' => threshold,
    'subfulfillments' => subfulfillments
  }
end

#validate(message: nil, **_kwargs) ⇒ Object 



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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 321

def validate(message: nil, **_kwargs)
  fulfillments = subconditions.select { |c| c['type'] == FULFILLMENT }

  min_weight = Float::INFINITY
  total_weight = 0
  fulfillments.each do |fulfillment|
    min_weight = [min_weight, fulfillment['weight'].abs].max
    total_weight += min_weight
  end

  # Total weight must meet the threshold
  return if total_weight < threshold

  valid_decisions = fulfillments.map do |fulfillment|
    if fulfillment['body'].validate(message: message, **_kwargs)
      [true] * fulfillment['weight']
    end
  end.compact.flatten
  valid_decisions.count >= threshold
end

#write_hash_payload(hasher) ⇒ Object

Raises:

  • (StandardError) 


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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 91

def write_hash_payload(hasher)
  raise StandardError, 'Requires subconditions' if subconditions.empty?

  _subconditions = subconditions.inject([]) do |store, c|
    writer = Utils::Writer.new
    writer.write_var_uint(c['weight'])
    writer.write(
      c['type'] == FULFILLMENT ? c['body'].condition_binary : c['body'].serialize_binary
    )
    store.push(writer.buffer)
  end
  sorted_subconditions = ThresholdSha256Fulfillment.sort_buffers(_subconditions)

  hasher.write_uint32(threshold)
  hasher.write_var_uint(sorted_subconditions.length)
  sorted_subconditions.each do |cond|
    hasher.write(cond)
  end
  hasher
end

#write_payload(writer) ⇒ Object

Raises:

  • (TypeError) 


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# File 'lib/cryptoconditions_ruby/types/threshold_sha_256_fulfillment.rb', line 212

def write_payload(writer)
  raise TypeError, 'writer must be a Writer instance' unless writer.is_a?(Utils::Writer)

  subfulfillments = subconditions.each_with_index.map do |c, i|
    next unless c['type'] == FULFILLMENT

    subfulfillment = c.dup
    subfulfillment.merge!(
      'index' => i,
      'size' => c['body'].serialize_binary.length,
      'omit_size' => c['body'].condition_binary.length
    )
  end.compact

  smallest_set = ThresholdSha256Fulfillment.calculate_smallest_valid_fulfillment_set(
    threshold, subfulfillments
  )['set']

  optimized_subfulfillments = subconditions.each_with_index.map do |c, i|
    if c['type'] == FULFILLMENT && !smallest_set.include?(i)
      subfulfillment = c.dup
      subfulfillment.update(
        'type' => CONDITION,
        'body' => c['body'].condition
      )
    else
      c
    end
  end

  serialized_subconditions = optimized_subfulfillments.map do |c|
    writer_ = Utils::Writer.new
    writer_.write_var_uint(c['weight'])
    writer_.write_var_octet_string(c['type'] == FULFILLMENT ? c['body'].serialize_binary : '')
    writer_.write_var_octet_string(c['type'] == CONDITION ? c['body'].serialize_binary : '')
    writer_.buffer
  end

  sorted_subconditions = ThresholdSha256Fulfillment.sort_buffers(serialized_subconditions)

  writer.write_var_uint(threshold)
  writer.write_var_uint(sorted_subconditions.length)
  sorted_subconditions.each { |c| writer.write(c) }
  writer
end