Substitution and transposition ciphers are two categories of ciphers used in classical cryptography. Substitution and transposition differ in how chunks of the message are handled by the encryption process. Substitution ciphers Substitution ciphers encrypt plaintext by changing the plaintext one piece at a time. The Caesar Cipher was an early substitution cipher. In the Caesar Cipher, each character is shifted three places up. Therefore, A becomes D and B becomes E, etc… This table shows “VOYAGER” being encrypted with the Caesar substitution cipher: Plaintext V O Y A G E Read More

Browser plugins are programs which extend your web browser by making it able to work with additional types of web content. Popular Browser Plugins Adobe Acrobat The Adobe Acrobat browser plugin enables you to view and print Adobe PDF files from within your web browser. Macromedia Flash Player Macromedia Flash Player is a browser plugin which enables you to view Macromedia Flash movies within your web browser. Macromedia Shockwave Player The Macromedia Shockwave Player enables your web browser to display Shockwave movies that are created with Macromedia Director. Sun Java Read More

Windows Hot Keys allow computer users to conduct specific Windows operating system (OS) functions without having to navigate to application menus, which saves time. A common task that can be accomplished through Window Hot Keys is flipping a computer screen upside down. The resulting display can also be reversed with a similar method or by using applications found in the Windows Control Panel. How to Flip a Computer Screen Upside Down with Windows Hot Keys Step 1 – Press the “Ctrl” + “Alt” + “Down Arrow” keys simultaneously. The computer Read More

TCP and IP are two seperate protocols. IP (Internet Protocol) is a network layer protocol, while TCP (Transmission Control Protocol) is a transport layer protocol. Every computer and network device attached to the Internet has at least one IP address. For example, the IP address of this web server is 66.37.153.81. Then, within each of those IP addresses, each computer and network device will have a number of TCP ports. For example, the web server software on this web server responds on TCP port 80 and the mail server software Read More

Understanding the Purpose of Host Names In TCP/IP based networks, the packets that are transmitted over the network contain the following IP addresses: The IP address of the computer sending the packet The IP address of the destination computer intended to receive the packet. The IP address information is used to forward the packet to the destination computer. The IP addresses of computers therefore have to be both unique and correct so that they can be forwarded to the correct destination. IP addresses also contain the following important information: Network Read More

To change a Yahoo Messenger Password, visit Yahoo: Change Password. Changing a Yahoo Messenger password changes all passwords for Yahoo’s personalized services including: Yahoo! Mail Yahoo! Chat My Yahoo! Yahoo! Finance The instructions to change a Yahoo Messenger password will only work if the user knows his/her current Yahoo Messenger password. If the user’s Yahoo Messenger password is lost, he/she should refer to How does Yahoo Messenger password recovery work?.

Configuring Linux DHCP Server Overview of Linux DHCP DHCP basically stand for the dynamic host configuration protocol. In other words you can say it describes that how your computer is attached with networks.. Assigning an IP address dynamically is basic task assigned to DHCP along domain name, name server, gateway, host name and net mask. DHCP can provide the other information like time server etc and has capability to save your lots configuration work in your organization and company as well. The Linux DHCP performs like this as mentioned above Read More

Computer worms are programs that reproduce, execute independently, and travel across network connections. The key difference between a virus and worm is the manner in which each reproduces and spreads. A virus is dependent upon the host file or boot sector and the transfer of files between computers to spread, whereas a computer worm can execute completely independently and spread on its own accord through network connections. The security threat from worms is equivalent to that of viruses. Computer worms are skilled enough to do serious damage such as destroying Read More

The TiVo is compatible with all Dish Network receivers that support IR control. IR control is provided all recent Dish Network receivers. However, there is no need to purchase a TiVo. Dish Network provides satellite receivers with built in DVR (Digital Video Recorder) capabilities. Dish Network provides two models of DVR receivers, one for standard definition and one for HDTV. Features of the Dish Network HDTV DVR include: Independently watch and record programming on two TVs TV1: View and record high definition or standard definition programming TV2: View and record Read More

Windows registry The Windows Registry is a focal database that holds all the settings pertaining to Windows operating systems. It includes data and settings for hardware, software, and user related information. Any change made to the system in terms of system settings, hardware or software is reflected in the Windows registry. The Windows registry can be used to view runtime information about active hardware and software, and it can also be used for troubleshooting and fixing Windows issues. However only advanced users can view and edit settings in the registry, Read More