class ActiveRecord::Encryption::Properties

See Properties::DEFAULT_PROPERTIES, Key, Message
message.headers.encrypted_data_key # instead of message.headers[:k]

a readable name.
for common properties that will keep these keys very short while exposing
efficiency to keep their keys as short as possible. It defines accessors
Since properties are serialized in messages, it is important for storage
Key (public tags) and Message (headers).
This is a wrapper for a hash of encryption properties. It is used by

def []=(key, value)

It will raise an +EncryptedContentIntegrity+ if the value exists

Set a value for a given key 
def []=(key, value)
  raise Errors::EncryptedContentIntegrity, "Properties can't be overridden: #{key}" if key?(key)
  validate_value_type(value)
  data[key] = value
end

def add(other_properties) 

def add(other_properties)
  other_properties.each do |key, value|
    self[key.to_sym] = value
  end
end

def initialize(initial_properties = {}) 

def initialize(initial_properties = {})
  @data = {}
  add(initial_properties)
end

def to_h 

def to_h
  data
end

def validate_value_type(value) 

def validate_value_type(value)
  unless ALLOWED_VALUE_CLASSES.find { |klass| value.is_a?(klass) }
    raise ActiveRecord::Encryption::Errors::ForbiddenClass, "Can't store a #{value.class}, only properties of type #{ALLOWED_VALUE_CLASSES.inspect} are allowed"
  end
end