A cookie (also called HTTP cookie, web cookie, Internet cookie, browser cookie, or simply cookie) is a small piece of data sent from a website and stored on the user's computer memory (Hard drive) by the user's web browser while the user is browsing internet.

Cracking is where someone edits a program source so that the code can be exploited or modified. "Cracking" means trying to get into computer systems in order to steal, corrupt, or illegitimately view data.

Shareware publishers encourage users to give copies of programs to friends and colleagues but ask everyone who uses that program regularly to pay a registration fee to the program's author directly. Commercial programs that are made available to the public illegally are often called warez.

A person or program collects login and password information from a legitimate user to illegally gain access to others, account(s).

An Ethical issue is a problem or issue that requires a person or organization to choose between alternatives that must be evaluated as right (ethical) or wrong (unethical). These issues must be addressed and resolved to have a positive influence in society.
Some of the common ethical issues are listed below:
(i) Cyber crime
(ii) Software Piracy
(iii) Unauthorized Access
(iv) Hacking
(v) Use of computers to commit fraud
(vi) Sabotage in the form of viruses.

Generally, the following guidelines should be observed by computer users:
(i) Honesty: Users should be truthful while using the internet.
(ii) Confidentiality: Users should not share any important information with unauthorized people.
(iii) Respect: Each user should respect the privacy of other users.
(iv) Professionalism: Each user should maintain professional conduct.
(v) Obey The Law: Users should strictly obey the cyber law in computer usage.
(vi) Responsibility: Each user should take ownership and responsibility for their actions.

A proxy server provides a gateway between users and the internet. It is a server, referred to as an “intermediary” because it goes between end-users and the web pages they visit online. A proxy server is essentially a computer on the internet that has an IP address of its own.

Encryption and decryption are processes that ensure confidentiality that only authorized persons can access the information.
Encryption is the process of translating the plain text data (plaintext) into random and mangled data (called cipher-text).
Decryption is the reverse process of converting the cipher-text back to plaintext. Encryption and decryption are done by cryptography. In cryptography a kev is a piece of information (parameter) that determines the functional output of a cryptographic algorithm.

A firewall is a computer network security based system that monitors and controls incoming and outgoing network traffic based on predefined security rules. A firewall commonly establishes a block between a trusted internal computer network and entrusted computer outside the network. They are generally categorized as network-based or host-based. Network based firewalls are positioned on the gateway computers of LANs [local area Network], WANS [Wide Area Network] and intranets.

Public key encryption is also called Asymmetric encryption. It uses the concept of a key value pair, a different key is used for the encryption and decryption process. One of the keys is typically known as the private key and the other is known as the public key.
The private key is kept secret by the owner and the public key is either shared amongst authorized recipients or made available to the public at large.
The data encrypted with the recipient's public key can only be decrypted with the corresponding private key.
A digital certificate in a client-server model of communication is one of the example of Asymmetric Encryption. A certificate is a package of information that identifies a user and a server. It contains information such as an organization's name, the organization that issued the certificate, the users' email address and country, and user's public key.
When a server and a client require a secure encrypted communication, they send a query over the network to. the other party, which sends back a copy of the certificate: The other party's public key can be extracted from the certificate. A certificate can also be used to uniquely identify the holder.

Software Piracy is about the copyright violation of software created originally by an individual or an institution. It includes:
(i) stealing of codes / programs and other information illegally and creating duplicate copies by unauthorized means and utilizing this data either for one's own benefit or for commercial profit.
(ii) Downloading software from illegal network sources.
An entirely different approach to software piracy is called shareware, acknowledges the futility of trying to stop people from copying software and instead relies on people's honesty.
Shareware publishers encourage users to give copies of programs to friends and colleagues but ask everyone who uses that program regularly to pay a registration fee to the program's author directly.
To prevent unauthorized access, Firewalls, Intrusion Detection Systems (IDS), Virus and Content Scanners, Patches and Hot fixes are used.