Malware detection based on a predetermined criterion

A method comprising:

• generating a whitelist of clean files for use in malware scanning, the whitelist indicating one or more files to be scanned using a data verification operation in preference to a malware scanning operation where generating the whitelist comprises:
• receiving, for each respective one of a plurality of files determined not to contain malware, data associated with said respective one of said plurality of files, and determining whether said data associated with said respective one of said plurality of files satisfies a predetermined criterion that is associated with a time required to process the respective file using a malware scanning operation;
• and
• for each respective file that satisfies the predetermined criterion, including the respective file in the whitelist and generating stored data that includes identification data used to identify the respective file and hash data to be used to perform a data verification operation.