When file encryption ends, CZIP X shows a confirmation message with some optionally actions and information to user about the archive. If you want, you can save those data in a report that can be saved as a .TXT file.
WARNING! Saving a report doesn’t apply any legal relevance to that file or to its contents. It won’t be a proof in any judicial trial. If you want to give legal relevance to that report, you should consider to apply a digital signature.
PLEASE NOTE: the report shows the SHA-256 hash sum of the archive amid other info; if your archive is not standard but self-locking or self-erasing, the hash is valid only if your archive still has 3 decryption attempts left. This happens because such archives get modified upon every failed decryption attempt, in order to store how many attems are still available; thus, the SHA-256 hash sum will change accordingly.