Ubuntu: The file content is encrypted, but currently not supported

While trying to extract a password protected/encrypted 7-Zip archive on a fresh Ubuntu 20.04 LTS, we got the following error:

An error occurred while extracting files. The file content is encrypted, but currently not supported.

To fix the problem, we just installed the p7zip-full package using the apt command.

sudo apt-get install p7zip-full;

After that, we were prompted as expected to input the decryption password and we were able to extract the archive.

Below is the information of the package that was retrieved by apt info.

sudo apt info p7zip-full
[sudo] password for bob: 
Package: p7zip-full
Version: 16.02+dfsg-7build1
Priority: optional
Section: universe/utils
Source: p7zip
Origin: Ubuntu
Maintainer: Ubuntu Developers <[email protected]>
Original-Maintainer: Robert Luberda <[email protected]>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Installed-Size: 4887 kB
Depends: p7zip (= 16.02+dfsg-7build1), libc6 (>= 2.14), libgcc-s1 (>= 3.0), libstdc++6 (>= 5)
Suggests: p7zip-rar
Breaks: p7zip (<< 15.09+dfsg-3~)
Replaces: p7zip (<< 15.09+dfsg-3~)
Homepage: http://p7zip.sourceforge.net/
Task: kubuntu-desktop, kubuntu-full, xubuntu-desktop, lubuntu-desktop, ubuntustudio-desktop, ubuntukylin-desktop, ubuntu-mate-core, ubuntu-mate-desktop
Download-Size: 1187 kB
APT-Manual-Installed: yes
APT-Sources: http://cy.archive.ubuntu.com/ubuntu focal/universe amd64 Packages
Description: 7z and 7za file archivers with high compression ratio
 p7zip is the Unix command-line port of 7-Zip, a file archiver that
 handles the 7z format which features very high compression ratios.
 p7zip-full provides utilities to pack and unpack 7z archives within
 a shell or using a GUI (such as Ark, File Roller or Nautilus).
 Installing p7zip-full allows File Roller to use the very efficient 7z
 compression format for packing and unpacking files and directories.
 Additionally, it provides the 7z and 7za commands.
 List of supported formats:
   - Packing / unpacking: 7z, ZIP, GZIP, BZIP2, XZ and TAR
   - Unpacking only: APM, ARJ, CAB, CHM, CPIO, CramFS, DEB, DMG, FAT,
     if non-free p7zip-rar package is installed), RPM, SquashFS, UDF,
     VHD, WIM, XAR and Z.
 The dependent package, p7zip, provides 7zr, a light version of 7za,
 and p7zip, a gzip-like wrapper around 7zr.

Create an encrypted 7zip archive with encrypted header as well (no filenames are visible)

In case you come to a scenario where you need to encrypt, password protect the contents of a 7zip archive and make sure that not even the filenames of the contents are visible, 7zip has your back! As you can see in the following example you can implement the above requirements very easily.

7z a -p"pbVfdPs27Dc" -mhe hello.7z file1.bin file2.doc files.*

The structure of the above 7z command is the following:

#Based on: 7z <command> [<switches>...] <archive_name> [<file_names>...]
7z a -p"Some [email protected]" -mhe <archive_name> [<file_names>...]

To break it down, it goes like this:

  • We used the <command> a, which instructs the tool to add the listed files to the listed archive (if the archive does not exist, it will create it).
  • The <switch> -p, allows you to set the password for the archive.
  • The second <switch> -mhe (or -mhe=on) it enables data and header archive encryption.
    In case you cannot find this switch at the manual, check the examples in the man page (This command works on GNU/Linux, it was tested on Fedora).