You can validate your STOP7 media using SHA1 checksums.
Do this by running the sha1sum program from a shell prompt against your ISO images and comparing the values returned against the checksums published here. For example on Linux with your CDROM drive as /dev/hdc you would use the command:
$ sha1sum /dev/hdc
The checksum files published here are signed with gpg. To verify the checksums came from BAE Systems, you can verify our digital signature on the checksums files. For example
gpg --verify-files STOP7.0.1sha1sum
gpg --verify-files STOP7.0.1sha256sum
Downloads:
STOP7.0.1sha1sum
STOP7.0.1sha256sum
XTS-SUPPORT-GPG-PUBKEY.asc