An improved Internet File Safety Information Center (IFSIC) is disclosed. The improved IFSIC allows an Internet user to look up the authenticity and safety information about a file or group of files by computing a hash value from the file or group of files and sending the hash value to a central server on the Internet to retrieve such information. A user identifier and other information can be sent to the central server along with the hash value. The improved IFSIC can be supported by targeted advertising, can provide file update information, can provide a better filter for files attached to email messages, and can be used to ensure the integrity of operating systems and installed programs.