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Cryptography

How to get common name (CN) from SSL certificate using openssl command

I configured and installed a TLS/SSL certificate in /etc/ssl/ directory on Linux server. I was wondering if can I find out the common name (CN) from the certificate using the Linux or Unix command line option?
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How to compile and install Tarsnap on a Ubuntu/Debian Linux

A Tarsnap service is a secure online backup system for Linux, OSX, *BSD or UNIX-like system. They encrypt and store data in Amazon S3. The services also use rsync-like algorithms, and only backup data that has been changed since the last dump. The backups are protected by a security key only known to a backup operator or sysadmin. How do I install a tarsnap client on a Ubuntu or Debian Linux system?
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The OpenSSH project released an ssh client bug info that can leak private keys to malicious servers. A man-in-the-middle kind of attack identified and fixed in OpenSSH are dubbed CVE-2016-0777 and CVE-2016-0778. How do I fix OpenSSH’s client vulnerability on a Linux or Unix-like operating system?
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Google Compute Engine scp Files on a Linux or Unix or Mac OS X

Scp command copies files between hosts on a network using ssh for data transfer. How do I use scp toefacilitate the remote file transfer using Google Compute Engine virtual machines on a Linux, OS X or Unix-like system?
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On 19th March 2015, multiple high and moderate severity level vulnerabilities released in OpenSSL, a Secure Sockets Layer toolkit used in a Linux and Unix-like systems. How can I fix these vulnerabilities on a CentOS/RHEL/Ubuntu and Debian Linux based server for OpenSSL versions 1.0.2a, 1.0.1m, 1.0.0r, and 0.9.8zf.? How do I verify that my Linux server has been fixed against the OpenSSL vulnerability?
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Howto Configure PFSense Site-to-Site IPSec VPN Tunnel For Remote Access

I work from a small office/home office and I need to set up an IPSec site-to-site VPN between a Cisco/OpeNBSD IPSec-enabled gateway and firewall running PFSense. How do I configure the VPN tunnel so that I can access remote subnet and servers behiend a Cisco firewall/router securely? How do I setup a tunnel mode configuration which will provide you with an encrypted site-to-site network, allowing networks at multiple remote locations to be able to securely communicate using my PFSense located in my SOHO?
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How To Setup SSH Keys on a Linux / Unix System

I recently read that SSH keys provide a secure way of logging into a Linux and Unix-based server. How do I set up SSH keys on a Linux or Unix based systems? In SSH for Linux/Unix, how do I set up public key authentication?
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HowTo: Create a Self-Signed SSL Certificate on Nginx For CentOS / RHEL

I operate a small web site on Cloud server powered by CentOS Linux v6.4. I would like to encrypt my site’s information and create a more secure connection. How do I create a self-signed SSL certificate on Nginx for CentOS/Fedora or Red Hat Enterprise Linux based server?
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GPG Change Passphrase Secret Key Password Command

I know how to cange a passphrase for openssh using ssh-keygen command. How do I change a GPG encryption key’s passphrase on Linux or Unix like operating systems? How do I change the passphrase of the secret key using gpg?
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Debian / Ubuntu: Install Duplicity For Encrypted Backup In Cloud

My cloud based backup service provider has ssh access to the backup system. How do I install and configure duplicity software for remote backups in incremental and encrypted format on Debian or Ubuntu Linux based desktop / laptop / server?
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