In short
This tool calculates a file's fingerprint, a string of characters that changes completely at the slightest modification. Use it to check that a download, such as an ISO image or an installer, is intact by comparing its fingerprint with the one published by the publisher, or to find out whether two files are identical. It calculates SHA-256 by default, or SHA-512, SHA-1 and MD5, the last two flagged as insufficient against deliberate tampering. If you paste the expected fingerprint, the algorithm is recognised and each file is declared matching or different. Several files can be processed together, and the list can be exported in the format of the sha256sum command. The file is read in chunks, up to 64 GB, without being loaded whole into memory or leaving your device.