File Checksum
Calculate and compare file checksums.
How to use this tool
Steps
- Obtain the expected checksum from the software publisher or another authenticated channel.
- Choose the same algorithm named by the publisher; values from different algorithms cannot be compared.
- Select the file and let the worker finish without modifying or re-downloading it.
- Compare the complete hexadecimal strings, preferably by copy/paste into a constant-time or exact text comparison rather than checking only the first characters.
Supported formats
- Input: any local file readable by the browser File API.
- Output: hexadecimal digest strings for the selected algorithms.
- A digest identifies exact bytes; changing one byte, metadata field, or archive timestamp normally changes the result.
Things to know
- A matching digest cannot detect malware when the trusted reference describes the same malicious file.
- CRC32 is an error-detection checksum, not a cryptographic integrity proof.
- MD5 and SHA-1 have known collision weaknesses.
- Large files take time to read and still consume device I/O and processing resources.