# Verifying the integrity of installation files

You can verify the integrity of downloaded files against checksums provided in `SHA256SUMS` or `SHA512SUMS` files on Debian mirrors. You can find them in the same places as the installation images itself. Visit the following locations:

- checksum files for CD images,

- checksum files for DVD images,

- checksum files for BD images,

- checksum files for other installation files.

To compute the checksum of a downloaded installation file, use

    sha256sum filename.iso

respective

    sha512sum filename.iso

and then compare the shown checksum against the corresponding one in the `SHA256SUMS` respective `SHA512SUMS` file.

The Debian CD FAQ has more useful information on this topic (such as the script `check_debian_iso`, to semi-automate above procedure), as well as instructions, how to verify the integrity of the above checksum files themselves.