The main disadvantage of the symmetric key encryption is that all authorized persons involved, have to exchange the key used to encrypt the data before they can decrypt it. If anybody intercepts the key information; they may read all message

Data being transferred via networks (e.g. the Internet, e-commerce), mobile telephones, wireless microphones, wireless intercom systems, Bluetooth devices and bank automatic teller machines.

Encryption has been used by militaries and governments to facilitate secret communication. It is now commonly used in protecting information within many kinds of civilian systems. It is also used to protect data in communication system

Cyberattacks are launched primarily or causing significant damage to a computer system or for stealing important information from an individual or from an organization.

Social Engineering is a method of getting passwords and information using human weakness. These crackers trick people, not software. They can use just the phone for getting information, they can pretend being your friend and talk to you on Internet Relay Chat(IRC) or by Instant messenger.

Software cracking is the most often used type of cracking which is nothing but removing the encoded copy protection. Password cracking can be perform either by using an automated program or can be manually realized.

Hacking leads to Identity theft or gaining personal information. Firewalls, passwords and user Id's, anti hacking software.

Hacking.

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).

(i) A cracker (also called a black hat or dark side hacker) is a malicious or criminal hacker.
(ii) A cracker is someone who breaks into someone else's computer system, often on a network, by passing passwords or licenses in computer programs.