I released crx_appid gem.
This gem calculates Google Chrome extension ID (unique for each extensions) from private key.
require 'crx_appid' pem = open("extension.pem").read CrxAppid.calculate(pem) CrxAppid.calculate_from_file("extension.pem")
It's convenient when you write an update manifest xml file.
Feel free to report any issue and patches welcome.