# File lib/paperclip/attachment.rb, line 288 def hash_key(style_name = default_style) raise ArgumentError, "Unable to generate hash without :hash_secret" unless @options[:hash_secret] require 'openssl' unless defined?(OpenSSL) data = interpolate(@options[:hash_data], style_name) OpenSSL::HMAC.hexdigest(OpenSSL::Digest.const_get(@options[:hash_digest]).new, @options[:hash_secret], data) end