Hi,

i updated my previous replies by "code" tags. Hopefully my proposals
for changing the encryption script are more readable now.
(I wonder how to avoid the double spacing between lines.)


> Maybe the begining of an answer ?

You are nearly there. Combine your two failed experiments:

xorriso -as mkisofs -r backup | aespipe -e aes256 > backup.iso

(I tested this with "cat" rather than "aespipe ...".)

Reasoning:
xorriso interprets commands. One of them is "-as". The first argument after
"-as" chooses the emulation mode. Either mode "mkisofs" or mode "cdrecord".
The further arguments up to the first "--" are then interpreted as
options of the emulated programs.

There is no xorriso command "-r". So without preceeding "-as" "mkisofs",
this yields the error message about "Not a known command".
Further, xorriso does not accept lonely words as input paths (unless
command -add_plainly enabled this). Such paths are rather submitted as
arguments of commands like -map or -add. So your path "backup" gets the
same complaint "Not a known command".

--------------------------------------------------------------------

If you run xorriso for backup purposes, consider to enable some extras
by -as mkisofs option --for_backup: MD5 checksums for superblock,
directory tree, overall ISO, and each data file in the ISO, recording
of ACL and xattr.

xorriso -as mkisofs --for_backup -r backup | aespipe -e aes256 > backup.iso


The checksums can be verified on the decrypted ISO (i guess

aespipe -d -e aes256 <backup.iso >backup_clear.iso

) by xorriso runs like:

xorriso -for_backup -indev backup_clear.iso -check_media --

(Note that the "-for_backup" used here is a xorriso command, not an
-as mkisofs option. To have an effect it must be executed before the
-indev command which loads the ISO tree and extra info.)

If verification errors or read errors are reported but the directory
tree is still ok, one can search for damaged data files by

xorriso -for_backup -indev backup_clear.iso -check_md5_r SORRY / --

This can also be done if the ISO is on optical medium or on USB stick

xorriso -for_backup -indev /dev/sr0 -check_media --
xorriso -for_backup -indev stdio:/dev/sdd -check_media --

The prefix "stdio:" is necessary because xorriso normaly refuses on
drive addresses under /dev/ if they do not lead to a SCSI/MMC device.
By the prefix you confirm that you want to use the /dev/ file like
a normal data file.

Recorded ACL and xattr can be listed by xorriso in the input format
of programs setfacl(1) and setfattr(1). The can be restored together
with the file data by xorriso if enabled by command -osirrox "on".

Have a nice day :)

Thomas


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