The most likely cause of the issue of having different hash values for a downloaded security tool is a modified file. A hash value is a unique and fixed-length string that is generated from an algorithm that processes data or files. A hash value can be used to verify the integrity and authenticity of data or files by comparing it with a known or expected value. If the hash values do not match, it means that the data or file has been altered or corrupted in some way. A modified file may result from intentional or unintentional changes, such as editing, encryption, compression or malware infection. Private-browsing mode is a feature that allows users to browse the web without storing any browsing history, cookies or cache on their browser. Private-browsing mode does not affect the hash value of a downloaded file but only how the browser handles user data. Invalid certificate is an error that occurs when a website or a server does not have a valid or trusted digital certificate that proves its identity and secures its communication. Invalid certificate does not affect the hash value of a downloaded file but only how the browser verifies the website or server's credibility. Browser cache is a temporary storage that stores copies of web pages, images and other content that users have visited on their browser.