If you know what the checksum of the original file is supposed to be, you can run the hashing algorithm on the downloaded file to make sure the two values match. How checksums keep you safeĬhecksums let you verify the integrity of downloaded files. If you change one little thing about that file, and run it through the hashing algorithm again, you get a totally different value. For this reason, if you compare two checksum values, you can tell whether or not they were derived from the same file. If you put a file through a hashing algorithm, you get a unique value. Here’s the main thing to remember about checksums: They act like a “fingerprint” for a file. The letters are only there because they’re numbers expressed in a non-decimal numeral system (the one above is hexadecimal). These checksum values look like a big string of letters and numbers, for example: 11a0241a5a7accb9e599eeff04e739479049d75669067980401451f3fde72b96īut they’re actually just really huge numbers. For our purposes, we’re going to simplify things and only talk about checksums generated by cryptographic hashing algorithms. A checksum is the value you get when you run a file’s bits and bytes through a special algorithm designed to produce - you guessed it - checksums. What is a checksum?įirst, what is a checksum? Here’s the dictionary definition, courtesy of Wikipedia:Ī checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. In this guide and walkthrough, we’ll show you how to use Terminal and checksums to verify your macOS app downloads. How do you know that the app you’ve downloaded is genuine, and not a macOS Trojan? Your Mac comes with a built-in tool that can help.

How to use checksums on Mac to verify app downloads

Checksum generate tool