Generates a unique digest using the session_id and the CSRF secret.

Source Code

# File action_controller/request_forgery_protection.rb, line 119
def authenticity_token_from_session_id
  key = if request_forgery_protection_options[:secret].respond_to?(:call)
    request_forgery_protection_options[:secret].call(@session)
  else
    request_forgery_protection_options[:secret]
  end
  digest = request_forgery_protection_options[:digest] ||= 'SHA1'
  OpenSSL::HMAC.hexdigest(OpenSSL::Digest::Digest.new(digest), key.to_s, session.session_id.to_s)
end