Glossary
What is a checksum?
MarkdownWhat it is
Common algorithms are MD5, SHA-1, SHA-256 and SHA-512. Developers publish the expected checksum next to a download.
Why it matters on a Mac
Comparing the published value with your own tells you whether the file arrived intact. MD5 and SHA-1 are fine for catching corruption but not for security. Use SHA-256 or longer when security matters.
How to check it on macOS
In Terminal, run shasum -a 256 /path/to/file. Compare the output with the published value.
How Toolbox handles it
Hash Generator computes MD5, SHA-1, SHA-256, SHA-384 and SHA-512 of text or files. Paste the expected checksum into Compare and it tells you which algorithm matches, or that it does not match. Find Duplicates also uses a SHA-256 of the whole file to confirm true duplicates.
Frequently asked questions
Is a checksum the same as encryption?
No. A hash cannot be reversed to get the file back.
What if the checksum does not match?
Download the file again. If it still differs, do not trust it.
Can I hash large files?
Yes. Hash Generator reads files in chunks.
