In this article, we will share some useful command-line tools that can be used to generate random passwords and also demonstrate how to encrypt and decrypt passwords with or without the salt method, which is a security enhancement used in password hashing.

Security has become a critical aspect of our digital lives. We use passwords for computers, emails, cloud services, mobile devices, documents, and much more. Everyone understands the importance of choosing a password that’s both easy to remember and difficult to guess.

What if we could let a machine generate secure passwords automatically using tools like pwgen or makepasswd, which are command-line utilities designed to create random passwords based on specified length, complexity, and character types?

PWgen – Generate a Random Password on Linux

To generate a random password with a length of 10 characters using the ‘pwgen‘ command, simply run:

<code>$ sudo apt install pwgen         [On <strong>Debian, Ubuntu and Mint</strong>]
$ sudo yum install pwgen         [On <strong>RHEL/CentOS/Fedora</strong> and <strong>Rocky/AlmaLinux</strong>]
$ sudo emerge -a sys-apps/pwgen  [On <strong>Gentoo Linux</strong>]
$ sudo apk add pwgen             [On <strong>Alpine Linux</strong>]
$ sudo pacman -S pwgen           [On <strong>Arch Linux</strong>]
$ sudo zypper install pwgen      [On <strong>OpenSUSE</strong>]    </code>

After installing ‘pwgen‘, you can generate a single password as follows:

<code>$ pwgen 10 1</code>

If you want to generate multiple unique passwords with a length of 50 characters at once, use this command:

<code>$ pwgen 50</code>

Makepasswd – Generate Unique Passwords on Linux

The makepasswd utility is another password generation tool that creates random passwords based on user-defined parameters such as length.

Before using makepasswd, ensure it is installed. If not, install it using your system's package manager:

<code>$ sudo apt install makepasswd         [On <strong>Debian, Ubuntu and Mint</strong>]
$ sudo yum install makepasswd         [On <strong>RHEL/CentOS/Fedora</strong> and <strong>Rocky/AlmaLinux</strong>]
$ sudo emerge -a sys-apps/makepasswd  [On <strong>Gentoo Linux</strong>]
$ sudo apk add makepasswd             [On <strong>Alpine Linux</strong>]
$ sudo pacman -S makepasswd           [On <strong>Arch Linux</strong>]
$ sudo zypper install makepasswd      [On <strong>OpenSUSE</strong>]    </code>

To generate a password with the default length of 10 characters:

<code>$ makepasswd </code>

For a password with 50 characters:

<code>$ makepasswd  --char 50</code>

To create 7 random passwords each containing 20 characters:

<code>$ makepasswd --char 20 --count 7</code>

mkpasswd – Encrypt a Password in Linux

To securely encrypt a password using crypt (a Python built-in library) along with a salt method.

For those unfamiliar, salt refers to random data added to a password before hashing, making it more resistant to dictionary and rainbow table attacks.

The mkpasswd command comes from the whois package and is not included by default in many modern Linux distributions. Install it using your distribution’s package manager:

<code>$ sudo apt install whois         [On <strong>Debian, Ubuntu and Mint</strong>]
$ sudo yum install whois         [On <strong>RHEL/CentOS/Fedora</strong> and <strong>Rocky/AlmaLinux</strong>]
$ sudo emerge -a sys-apps/whois  [On <strong>Gentoo Linux</strong>]
$ sudo apk add whois             [On <strong>Alpine Linux</strong>]
$ sudo pacman -S whois           [On <strong>Arch Linux</strong>]
$ sudo zypper install whois      [On <strong>OpenSUSE</strong>]    </code>

Now execute the mkpasswd command to hash a password using salt. The salt value is generated randomly each time, resulting in different outputs even for the same input.

<code>$ mkpasswd tecmint</code>

This command generates a salted hash for the password “tecmint.” Each execution produces a unique result due to the random salt.

To generate an SHA-512 hash for the password “tecmint”, use:

<code>$ mkpasswd -m sha-512 tecmint</code>

The output will be the encrypted hash suitable for storage or authentication.

Additionally, mkpasswd supports interactive mode — if you omit the password from the command line, it will prompt you to enter one.

Encrypt a String with Password in Linux

To encrypt a string such as “Tecmint-is-a-Linux-Community” using aes-256-cbc encryption with a password “tecmint” and salt:

<code>$ echo Tecmint-is-a-Linux-Community | openssl enc -aes-256-cbc -a -salt -pass pass:tecmint -pbkdf2</code>

In the above example, the echo command sends the string into the openssl command via a pipe. It uses the enc utility with the aes-256-cbc cipher, applies salt, and derives the key using the PBKDF2 algorithm with the provided password.

Decrypt a String in Linux

To decrypt the previously encrypted string using the openssl command and the -aes-256-cbc decryption option:

<code># echo U2FsdGVkX18Zgoc dfAdpIK58JbcEYFdJBPMINU91DKPeVVrU2k9oXWsgpvpdO/Z | openssl enc -aes-256-cbc -a -d -salt -pass pass:tecmint</code>

That concludes this guide. If you have any other useful tips or tricks, feel free to share them in the comments section below. Your suggestions may be featured under your name and included in upcoming articles.

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