August 31, 2008, 1:01 pm
Lets start with some basics….
“/etc/passwd” file: the password database
Our Linux system stores its usernames and passwords in a special file : ‘/etc/password’. The passwords in this file are one way encrypted (hash-ed) through a password encryption function called ‘crypt’ using DES as the encryption algorithm. The good thing about ‘hashing’ is that you can not ‘decrypt’ the hashed passwords because the function used for hashing cannot be reversed (one-way traffic). DES generally uses keys (symmetric key cryptography) in which case things can be either encrypted or decrypted, but for encrypting passwords in Linux, only the ‘hashing’ implementation of DES is used.
Continue reading ‘Linux password policies’ »
March 13, 2008, 1:34 am
I decided to write this as a subsection of Root, Superuser, and User Management Basics as that was getting rather lengthy. There is a bit more to understand about managing users, groups, and super-user permissions. We’ve already covered how to add a user, delete a user, add a group, delete a group, rename a group, and how to reset a user’s password. Now what we didn’t go into depth was, all of this information is controlled by a number of files and these commands modify these files. These files can be manually editted though to accomplish the same thing or for more detailed management.
Continue reading ‘Understanding /etc/passwd, /etc/group, /etc/sudoers, and /etc/skel/’ »
