On Thu, Jul 16, 2020 at 02:32:49PM -0600, the...@sys-concept.com wrote:
> zip - has a switch "-e" encrypt
>
> It works from command line but I'm not sure how to enter it in XFCE in
> in custom action that will appear in file manager context menu.
>
> I have 7za that works:
> 7za a file.zip %N -tzip -mem=AES256 -mx9 -pxx
>
> but zip:
> zip file %N -ex
7za accepts the password as part of the command-line invocation, and zip does
not. It's actually quite appalling, from a security perspective, that 7za
allowing the echoing and saving (in the history) of the password. From the
manual page of zip(1):
-e
--encrypt
Encrypt the contents of the zip archive using a password which
is entered on the terminal in response to a prompt (this will
not be echoed; if standard error is not a tty, zip will exit
with an error). The password prompt is repeated to save the user
from typing errors.
Since it requires stderr (although I think this should be "stdin") on the
terminal, you probably won't be able to set this up to use be a context menu
option, unless you want to make the context menu button invoke a terminal
window; that's probably the only plausible solution.
> And I have no clue where did I get in 7za parameter: -mem=AES256 -mx9
Again, this can be explained by reading the manual page of 7za(1), although it
does require a bit of extra digging, and probably requires p7zip to be emerged
with the `doc` USE-flag. The "-mx[=]9" option is explained in the "EXAMPLE 1"
section of the man page:
-mx=9 level of compression = 9 (Ultra)
I also think you made a slight error when typing "-mem=AES256". The "-mem"
option does exist, but it is used to specify the amount of memory used by PPMd,
not any sort of encryption algorithm:
mem={Size}[b|k|m|g]
Sets the size of memory used for PPMd. You must specify the size
in bytes, kilobytes, or megabytes. The maximum value is 2GB =
2^31 bytes. The default value is 24 (16MB). If you do not
specify any symbol from the set [b|k|m|g], the memory size will
be calculated as (2^Size) bytes. PPMd uses the same amount of
memory for compression and decompression.
"-em", however, makes a lot more sense, and is used to set the encryption method
on the "zip" module:
em={EncryptionMethodID} [default: ZipCrypto]
Sets a encryption method: ZipCrypto, AES128, AES192, AES256
To find the full documentation of the various switches on your system, emerge
p7zip with `doc` and execute `qfile method.htm` and find the relevant file
belonging to p7zip. The docs are really impressive and comprehensive, should you
want to learn more about becoming a power-user of p7zip (I am not one; I just
installed it now to investigate your issue).
Hope this helps,
Ashley.
--
Ashley Dixon
suugaku.co.uk
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