How to generate Encrypt/Decrypt Random Passwords

So by default it will generate the passwords with 8 characters and 8 columns for 20 rows.
If you want to generate the single password with 10 characters, enter the command as follows

[user1@linuxhelp~]$ pwgen 10 1
chuPhew2ch

Whereas to generate 4 passwords with 6 characters each then, enter the values accordingly

[user1@linuxhelp~]$ pwgen 6 4
ai5EiT thai7O oPhoo6 hequ6U

Now to generate a single password for a length of 55 characters then, the output will be as follows

[user1@linuxhelp~]$ pwgen 55
ohqui1Euch4quie4Aexoo0ViephouseiQue1jeijaecui5tee8peiCh
Aes7aigaeJahjahshohquohShaimuucoojiew3thaepev7Shohb6Thu
oa3ohx4phae1mei2Aeyoo6eenaiD1aiv0iqueif7tophe4fahy8gahg
ru0oofieb6aeghiengee6ahJeiGhee1ung4eeC6jaitiSiuF5igha4T
choo1ebahPitiex4theenia8yoo2uSio8uagooKuoR6onieshai6du0
keeMahph1ahw2PeiNahpaithenaexov9Ie2sha2gaenei4gohy4Ai0c
AiMeeg5koh1cai1quieQu3ej9aeMioPoh2kahPh5ohhoh5luKohbeja
eeyeid4ongo6aeph9togohm9uash8ad9caiteesha8aDoovai1saz7a
saeru9aeLosh8fiesheeheen1seiza1uvoit3Tei2Mieth7aex7eNga
uup7ahw0Ahj7ohmuize9evaimi4xajeegheigaewohkochaeri3oing
ahgieto2uxie1ahghoopooSohpai4heosas1faiw8jeidoyahj9eeth
saewe8Yei6oocie9fae6iefaeMoo6ohWabeifoo1ahN1pheu6IThied
RuD0aingahc7zuofi7Voh8uvoon7ieye3QuooShieJeiraeKiezei7j
aiphooP1AshequeiRequau6xei5xishuuPohpahboopethei6Tieyeb
eeQu6ithahthoghochoht8poyahc9Ahku4chediexaeghaSohBohfah
pooh0Yeecairai8hahP2ooy2shaiyo8reish8fohch1Caejaevi5hoh
kootee6oech3thei9Phohpae2neelieZoom9fiejuSh2ohhaic5vah2
ohw6ea6quae4oongoodei6Uo0jie5zi8phoh3eiceemeeN8eeyochuk
iipae6ooyoheenileesha4saeyohZaCh9eeCu1ungaez6cheiwa9Agi
ahNgooh5aiNga8ujuK4OhLouvu8Eileephohthie2oog6moZeeXeeph

mkpasswd

The mkpasswd installation process can’ t be done directly since its not available in yum. It is located as a dependency of another package. To check, run the following command.

[root@linuxhelp~]# yum whatprovides */mkpasswd
&hellip 
&hellip 
expect-5.44.1.15-5.el6_4.x86_64 : A program-script interaction and testing utility
Repo        : base
Matched from:
Filename    : /usr/bin/mkpasswd
&hellip 
&hellip 

So it will show that the mkpasswd is located in expect package, at first we need to install that package.

[root@linuxhelp~]# yum install expect
 Loaded plugins: fastestmirror, refresh-packagekit, security
Setting up Install Process
Loading mirror speeds from cached hostfile
 * base: centos.webwerks.com
 * epel: epel.mirror.net.in
* extras: centos.webwerks.com
* updates: centos.webwerks.com
Resolving Dependencies
-->  Running transaction check
--->  Package expect.x86_64 0:5.44.1.15-5.el6_4 will be installed
&hellip 
&hellip 
Installed:
expect.x86_64 0:5.44.1.15-5.el6_4                                                                    
Complete!

Just run mkpasswd command to generate the encrypted password, it will generate a character value length of 10 since it’ s the default value.

[user1@linuxhelp~]$ mkpasswd 
#63aJWtsz

To Generate a random password of character length of 25

[user1@linuxhelp~]$ makepasswd -l 25
mqjvjJP0zwih7pad[vhztkwlt

It will generate the password with two digits in it.

To generate a password with 4 digits with the length of 25

[user1@linuxhelp~]$ makepasswd -l 25 -d 4
ibo7Mr~V1azava87zsdxjlenw

To generate some special characters in the password

Use -s option to generate some special characters in the password.

[user1@linuxhelp~]$ mkpasswd -s 3
m 3f& 1WH(

It generates the password with 3 special characters.

We can also set the encrypted password for the user,

[root@linuxhelp~]# mkpasswd user1
kn1Y[yJ1n

It will generate the password and will be assigned to the user1.

Openssl

It is one of the important cryptography concept to encrypt and decrypt the contents.

To encrypt the given content using openssl

[user1@linuxhelp ~]$ echo helloworld | openssl enc -aes-256-cbc -a 
enter aes-256-cbc encryption password:
Verifying - enter aes-256-cbc encryption password:
U2FsdGVkX18uIbo6xS9XcD+GLR0C1P5O0y5jd6+C6Wc=

Here, enc stands for Encoding with Cipher and aes-256-cbc is also an encryption cipher.
-a option is to intimate OpenSSL to encrypt in Base64-ensode format.

To decrypt follow the same command with the encrypted content as input

[user1@linuxhelp ~]$ echo U2FsdGVkX18uIbo6xS9XcD+GLR0C1P5O0y5jd6+C6Wc= | openssl enc -aes-256-cbc -a -d  
enter aes-256-cbc decryption password:
hello world

We can give the password from the command itself for that -pass option is to be used at last with password mentioned.

[user1@linuxhelp ~]$ echo hello world | openssl enc -aes-256-cbc &ndash a -pass pass:linux 
U2FsdGVkX18uIbo6xS9XcD+GLR0C1P5O0y5jd6+C6Wc=
[user1@linuxhelp ~]$ echo U2FsdGVkX18uIbo6xS9XcD+GLR0C1P5O0y5jd6+C6Wc= | openssl enc -aes-256-cbc &ndash a &ndash d &ndash pass pass:linux 
hello world

To encrypt the contents of the file

[user1@linuxhelp test]$ cat test.txt
Hello linuxhelp
[user1@linuxhelp test]$ openssl enc -aes-256-cbc -in test.txt -out test.txt.enc
enter aes-256-cbc encryption password:
Verifying - enter aes-256-cbc encryption password:

Now the file is encrypted and saved into the new file called test.txt.enc, we can remove the original file.

[user1@linuxhelp test]$ cat test.txt
Salted__"  R ?
~ ` g b?

[user1@linuxhelp~]$ openssl enc -aes-256-cbc -d -in test.txt.enc -out test.txt
enter aes-256-cbc decryption password:

[user1@linuxhelp test]$ cat test.txt
Hello linuxhelp