Paperpass repeated inspection will not be stolen. It is usually safe to use PaperPass for repeated inspection. PaperPass adopts multiple protection measures to ensure the confidentiality of papers and encrypt uploaded papers. In the case of normal inspection in official website, papers are usually not leaked. Regular duplicate checking systems will generally strictly abide by relevant laws and regulations, and will not easily disclose the papers submitted by users for testing. PaperPass website was born in 2007, which is the first Chinese document similarity comparison system in the world. After four years of operation, it has developed into the most authoritative and reliable online website for checking and preventing plagiarism in China's original field. The currently used beta version was developed after absorbing a large number of users' opinions. The comparison algorithm is updated, which greatly improves the efficiency and accuracy of comparison. In addition, practical functions such as downloading report and similarity distribution map are added.