My Experiments for Truth.

If someone wants you to send a confidential file. ######################################## 1)   Generate  gpg keys from your local machine and provide them your public key. 2)   Then they will encrypt that file with your public key provided by you via mail or chat. 3)   Now after encryption they will send that encrypted file to you. 4)   Now you can decrypt the file with the private key resides in your local machine. Useful commands. ############### Generate gpg key # gpg --gen-key Export a public key  #  gpg --armor --export ramesh > ramesh-pub-asc.gpg Import a public key #  gpg --import FileName If you want to send a file ##################### 1)   Ask his/her the public key. 2)   Import the public key. 3)   encrypt the file 4)   Send them the file. That is all , Thanks,

FOR APACHE $ sudo apt-get update $ sudo apt-get install software-properties-common $ sudo add-apt-repository ppa:certbot/certbot $ sudo apt-get update $ sudo apt-get install python-certbot-apache First given a command like this : sudo certbot --apache -d cloud.xyz.com If this gave an error like below: Performing the following challenges: Client with the currently selected authenticator does not support any combination of challenges that will satisfy the CA. Then give the below command and it works. # certbot --authenticator standalone --installer apache --pre-hook "apachectl -k stop" --post-hook "apachectl -k start" Saving debug log to /var/log/letsencrypt/letsencrypt.log Plugins selected: Authenticator standalone, Installer apache No names were found in your configuration files. Please enter in your domain name(s) (comma and/or space separated)  (Enter 'c' to cancel): cloud.xyz.com Running pre-hook command: apachectl -k stop Obtaining