Our meeting on December 17th included two presentations: “Multiple Passwords With A Script” along with a demo, and a demo of the Bash command: “lsof”
Report on “Multiple Passwords With A Script”
“Multiple Passwords With A Script” was an article that I submitted in May but which finally appeared in the November issue of the free Full Circle Magazine #91 on pp. 16-17 that can be found at http://dl.fullcirclemagazine.org/issue91_en.pdf . The article refers to my menu-driven Bash script which gives simple options for encrypting and decrypting files. It uses a Linux program called ‘ccrypt’ that employs a symmetric key using a 256-bit Rijndael block cipher to do the encryption.
Symmetric keys are simpler and more appropriate for individuals not sharing their files with another person. Asymmetric keys such as those used by PGP are meant for a number of individuals sharing files. Asymmetric keys consist of a private one kept safe by the originator of the file and a public key that is shared among all of the individuals needing to decrypt the file.
A typical example of a page needing symmetric key encryption would be a text or spreadsheet page in clear-text that contains a simple listing of passwords made by a user for their own use. Ccrypt takes that page and makes a new one that is fully encrypted. Once done, the clear-text page is deleted. Decrypting the new page reverses the process giving back the original clear-text page while deleting the encrypted one. The only wrinkle, of course, is that the master password to use with ccrypt operations must be never be forgotten. However, the process of encrypting and decrypting files is made easy using this method.
Some of the readers of my Full Circle Magazine article needed some additional hints to get started with their personal situations. I’ve since fielded some of the items and hopefully copies of those hints will also appear in letters to the editor in next month’s Full Circle Magazine. A visit to the download section of http://fullcirclemagazine.org also allows ways to obtain past issues of the magazine.
Demo of the Bash Command: “lsof”
The Bash command on the command screen of “lsof” (without the quotes) allows the user to study what’s happening behind the scenes in a Linux computer by looking at listings of open files. Typically one would like to know what ports are open, what network activity is happening, and all the dependent library files that are in use.
Jim Ritterbusch demonstrated a number of examples showing various categories of files that might need further study. This way to study the activity going on in a computer is a nifty way to validate some of the security choices that have been made with that computer. It is also useful for determining what might be slowing the performance of the computer. The command: “man lsof” (without the quotes) gives the user’s manual description of the options available when using lsof.
Next Linux SIG Meeting
At the January 21st meeting in the DACS Resource Center of Ives Manor, no new presentations are scheduled at the moment. However, attendees can raise topics and issues as they feel the need to do so. We will continue to help with individuals migrating their older Windows computers to Linux. This is the Linux community’s normal way of sharing and using open-source software–which we mirror when we meet for our SIG.
Linux SIG meetings are for the beginner, intermediate or advanced user, and topics vary considerably depending upon the interests of the attendees. We cover software and hardware issues of individual attendees. Check the DACS Forum (Linux) or the DACS Meetup at http://www.meetup.com/DACS-Danbury-CT-Computer-User-Group/ for updates.