KMU Cyber Security Tutorials
"Welcome to Kapasa Makasa University Cyber Security Tutorials! We are dedicated to providing high-quality educational resources and tutorials on all things related to cyber security. Whether you are a beginner looking to learn the basics or an experienced professional seeking to expand your knowledge, our tutorials cover a wide range of topics. Discover the fundamentals of communication skills, information systems security, network design & administration, secure software engineering, network security, and cryptography. Our tutorials are designed to be accessible and engaging, offering clear explanations and practical examples. Stay up-to-date with the latest trends and best practices in the ever-evolving field of cyber security. Our experienced instructors and industry experts ensure that the content is relevant and reflects the current landscape of threats and countermeasures. Take advantage of our comprehensive resources to enhance your skills, gain confidence, and advance your career in the exciting world of cyber security. Join us on this educational journey and empower yourself to protect digital systems, secure sensitive information, and contribute to a safer online environment. Start exploring our tutorials today and unlock the potential of cyber security expertise at Kapasa Makasa University!"
Mary Chanda studying in the KMU Library
Jeff Sichilongo and Marry Chanda taking pics after class at K block classes
Nchimunya Faith Moono at the KMU Library
George Mwape, Nchimunya Faith Moono, Tracy Tembo, and Jeff Sichilongo at LT2 after Cryptography presentations
Network Security
OSI Reference Model
The Open Systems Interconnection model (OSI Model) was first introduced in the late 1970s. It is a reference model for designing a network architecture that is robust and flexible. It is a universally accepted model which describes the communication of various applications over the internet.
The OSI Model is divided into 7 layers: In order to reduce the design complexity, networks are organized as stacks of layers and levels. Each layer has its own set of functions which aids in the successful transfer of data. Each layer passes the data to the layer immediately below or above it.
The Layers are as follows:
- Application Layer – It consists of application layer protocol that allows network applications to work correctly in the network
- Presentation Layer – It receives the data from the application layer and is responsible for Translation, Data Compression, and Encryption/Decryption of the data
- Session Layer – It is responsible for setting up and managing connections. Its functions include Authentication, Authorization, and Session Restoration
- Transport Layer – It receives the data from the Session Layer. It is responsible for the delivery of a message from one process to another. It controls the reliability of communication through flow control, error control, and segmentation. It has two protocols namely TCP and UDP
- Network Layer – It is responsible for the transmission of data segments from one computer to another located in different networks
- Data Link Layer – Responsible for moving frames from one hop to another
- Physical Layer – It is responsible for converting the binary bits into signals and transmitting over local media
TCP/IP Reference Model
The layers in the TCP/IP protocol suite do not exactly match those in the OSI model. The original TCP/IP protocol suite was defined as having four layers: host to network, internet, transport, and application. TCP/IP Reference Model is the practical implementation of the theoretical OSI Model.
Transport Layer: The layer below the Session Layer is called the Transport Layer. The Data in this layer is called a segment. It is responsible for the delivery of a message from one process to another. It is also responsible for reliable communication through flow control, error control, and segmentation. Some of the most important protocols are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).
Transmission Control Protocol (TCP): It is a connection-oriented protocol that is used for the reliable transfer of data from one process to another process. It takes the help of the Port numbers for transmission. It uses flow control and error control mechanisms at the transport level. There are three phases in which TCP transmits the data between the sender and receiver: Connection Establishment, Data transfer, and Connection termination.
User Datagram Protocol (UDP): It is a transport layer protocol. It is an unreliable and connectionless protocol. It is much faster, simpler, and efficient than TCP. However, it doesn’t check errors due to which Bandwidth is saved. It is widely used in real-time services like video game, voice, or video communication.
Real-Life Examples of TCP
- Text Communication – We all are aware of the importance of Text Communication in the present times. Any discrepancy in texting between sender and receiver cannot be tolerated. Hence TCP is used in Text Communication due to its reliable transmission, error control, and in order receiving of the data. Example: Whatsapp, Instagram, Google Chat, iMessage.
- Transfer of files or FTP – TCP is used in File transfer when we cannot tolerate the loss of data and receiving the data in incorrect order is of utmost importance. FTP uses two TCP connections: control connection and data connection. Control Connection: FTP sends information like user identification and passwords. Data Connection: In this connection, files are sent over the network. Example: FileZilla Client and Server.
- HyperText Transfer Protocol (HTTP) – It is used to access the data present on the World Wide Web. It uses TCP protocol for accessing the web pages present on the internet due to the fact that TCP provides in order data, error control, and flow control, and retransmission of data segments.
- Simple Mail Transfer Protocol (SMTP) – It is an application layer protocol that is used to send Emails from one system to another. SMTP uses the services of TCP to start a connection with the SMTP server. Once the SMTP server accepts the connection request, it allows the sender to send the mails. Example: Yahoo, Gmail, Outlook, etc.
Real-Life Examples of UDP
- Online Games – Most of the online games we play use the services of User Datagram Protocol. Since any amount of delay cannot be tolerated in online games, UDP is widely used over TCP, which is quite slower. UDP doesn’t retransmit the lost data and is a connectionless protocol due to which it is much faster. Example: All online games.
- Video Conferencing – Video Conferencing apps like Skype, Gmeet, Zoom, all use the services of UDP due to the fact that they are real-time applications and any delay in receiving the data cannot be tolerated. Example: Skype, Google Meet, Zoom, and Facetime.
- Voice Over IP (VoIP) – It is similar to Video Conferencing, where apps like Viber, Whatsapp, Google Hangouts use UDP for converting our voice to digital data and transmit it over the network, hence the name VoIP. Example: Viber, Whatsapp Voice calling, Wi-Fi calling.
- Domain Name System (DNS) – It is a service used for mapping domain names to their corresponding IP address. It is used by the application layer. DNS uses UDP for fetching the corresponding IP address due to its speed and small request sizes. Example: DNS lookup requests.
