As many organizations move away from paper documents to digital documents, digital signatures are required to manage any sensitive digital documents. Digital signatures can be used to authenticate the source of the message, such that the receiver can decide whether to trust the sender or not. Now-a-days it is most widely used for software distribution [...]
Lakshmanan Ganapathy
Using GnuPG gpg command you can generate public and private keys. In this tutorial, we will use the keys generated by gpg command to send and receive encrypted files, and digitally sign a file. Encrypt a file and send it to your Friend 1. Import your friend’s public key When you want to send a [...]
tr is an UNIX utility for translating, or deleting, or squeezing repeated characters. It will read from STDIN and write to STDOUT. tr stands for translate. Syntax The syntax of tr command is: $ tr [OPTION] SET1 [SET2] Translation If both the SET1 and SET2 are specified and ‘-d’ OPTION is not specified, then tr [...]
Every file in Linux is associated with timestamps, which specifies the last access time, last modification time and last change time. Whenever we create a new file, or modify an existing file or its attributes, these timestamps will be updated automatically. Touch command is used to change these timestamps (access time, modification time, and change [...]
GnuPG stands for GNU Privacy Guard. GnuPG is an open implementation of OpenPGP ( Pretty Good Privacy ) standard as defined in RFC 4880. In this article we will cover the installation and the basics of generating keys using gnupg. This article is part of our ongoing series on Cryptography. If you are new to [...]
Bitwise operators are used to manipulate one or more bits from integral operands like char, int, short, long. In this article, we will see the basics of bitwise operators, and some useful tips for manipulating the bits to achieve a task. This article assumes that you know the basics of Truth Table for various operators. [...]
On Debian Lenny (and previous versions of Debian), you might have got tired of seeing a blue box with black background for GRUB when the Linux was booting up. But starting from Debian Squeeze, GRUB adds a background image which looks good (better than the boring background colors). This article explains how to change the [...]
lsof stands for List Open Files. It is easy to remember lsof command if you think of it as “ls + of”, where ls stands for list, and of stands for open files. It is a command line utility which is used to list the information about the files that are opened by various processes. [...]