1. Chapter 1 : Security Conceptby
Wienz

2. Security Application Security Computing Security Data Security
Information Security
Network Security

3. Application Security

4. Computing Security

5. Social Engineering
Social engineering is the act of manipulating people into performing actions or divulging confidential information, rather than by breaking in or using technical hacking techniques.
While similar to a confidence trick or simple fraud, the term typically applies to trickery or deception for the purpose of information gathering, fraud, or computer system access; in most cases the attacker never comes face-to-face with the victim.

6. Eavesdropping
Eavesdropping is the act of secretly listening to the private conversation of others without their consent, as defined by Black's Law Dictionary. This is commonly thought to be unethical and there is an old adage that eavesdroppers seldom hear anything good of themselves.

7. Man-in-the-middle Attack
In cryptography, the man-in-the-middle attack (often abbreviated MITM), or bucket-brigade attack, or sometimes Janus attack, is a form of active eavesdropping in which the attacker makes independent connections with the victims and relays messages between them, making them believe that they are talking directly to each other over a private connection, when in fact the entire conversation is controlled by the attacker. The attacker must be able to intercept all messages going between the two victims and inject new ones, which is straightforward in many circumstances (for example, an attacker within reception range of an unencrypted Wi-Fi wireless access point, can insert himself as a man-in-the-middle).

8. Man-in-the-middle Attack

9. Trojan
A Trojan horse (sometimes shortened to trojan), is non-self-replicating malware that appears to perform a desirable function for the user but instead facilitates unauthorized access to the user's computer system. The term is derived from the Trojan Horse story in Greek mythology.
Malware, short for malicious software, is software designed to infiltrate a computer system without the owner's informed consent.

10. Computer Virus
A computer virus is a computer program that can copy itself and infect a computer. A true virus can only spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, CD, DVD, or USB drive. Viruses can increase their chances of spreading to other computers by infecting files on a network file system or a file system that is accessed by another computer.

11. Computer Worm
A computer worm is a self-replicating computer program. It uses a network to send copies of itself to other nodes (computers on the network) and it may do so without any user intervention. This is due to the poor security the computers infected have. Unlike a virus, it does not need to attach itself to an existing program. Worms almost always cause at least some harm to the network, if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.

12. Denial-of-service Attack
A denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a computer resource unavailable to its intended users. Although the means to carry out, motives for, and targets of a DoS attack may vary, it generally consists of the concerted efforts of a person or people to prevent an Internet site or service from functioning efficiently or at all, temporarily or indefinitely. Perpetrators of DoS attacks typically target sites or services hosted on high-profile web servers such as banks, credit card payment gateways, and even root nameservers.

13. Denial-of-service Attack

14. Backdoor
A backdoor in a computer system (or cryptosystem or algorithm) is a method of bypassing normal authentication, securing remote access to a computer, obtaining access to plaintext, and so on, while attempting to remain undetected. The backdoor may take the form of an installed program (e.g., Back Orifice), or could be a modification to an existing program or hardware device.

15. Rootkit
A rootkit is a software system that consists of one or more programs designed to obscure the fact that a system has been compromised. Contrary to what its name may imply, a rootkit does not grant a user administrator privileges, as it requires prior access to execute and tamper with system files and processes. An attacker may use a rootkit to replace vital system executables, which may then be used to hide processes and files the attacker has installed, along with the presence of the rootkit. Access to the hardware, e.g., the reset switch, is rarely required, as a rootkit is intended to seize control of the operating system.

16. Key Logger
Keystroke logging (often called keylogging) is the practice of tracking (or logging) the keys struck on a keyboard, typically in a covert manner so that the person using the keyboard is unaware that their actions are being monitored.

17. Data Security
Data security is the means of ensuring that data is kept safe from corruption and that access to it is suitably controlled. Thus data security helps to ensure privacy. It also helps in protecting personal data.

18. Data Security Data Masking
Data masking is the process of obscuring (masking) specific data elements within data stores. It ensures that sensitive data is replaced with realistic but not real data. The goal is that sensitive customer information is not available outside of the authorized environment.

19. Data Security Data Erasure
Data erasure is a method of software-based overwriting that completely destroys all electronic data residing on a hard disk drive or other digital media. Permanent data erasure goes beyond basic file deletion commands, which only remove direct pointers to data disk sectors and make data recovery possible with common software tools.

20. Information Security
Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification or destruction. The terms information security, computer security and information assurance are frequently incorrectly used interchangeably. These fields are interrelated often and share the common goals of protecting the confidentiality, integrity and availability of information; however, there are some subtle differences between them.

21. Network Security
In the field of networking, the specialist area of network security consists of the provisions made in an underlying computer network infrastructure, policies adopted by the network administrator to protect the network and the network-accessible resources from unauthorized access, and consistent and continuous monitoring and measurement of its effectiveness (or lack) combined together.