What is a Password?

In computing, a password is a word or string of characters that is entered, often along with a user name, into a computer system to log in or to gain access to some resource. Passwords are a common form of authentication. Full security requires that the password be kept secret from those not allowed access.

The use of passwords goes back to ancient times. Sentries guarding a location would challenge for a password or watchword. They would only allow a person in if they knew the password. In modern times, passwords are used to control access to protected computer operating systems, mobile phones, cable TV decoders, automated teller machines (ATMs), etc. A typical computer user may require passwords for many purposes: logging in to computer accounts, retrieving e-mail from servers, accessing programs, databases, networks, web sites, and even reading the morning newspaper online.

Despite the name, there is no need for passwords to be actual words; indeed passwords which are not actual words are harder to guess, a desirable property. Some passwords are formed from multiple words and are more accurately called a passphrase. The term passcode is sometimes used when the secret information is purely numeric, such as the personal identification number (PIN) commonly used for ATM access. Passwords are generally short enough to be memorized.

Passwords vary in the degree of public awareness, security protection and frequency of change. The most public, and therefore least secure, password might be one that is given to members of a group, a committee or some other organization. For instance, "publiclibrary", "internet", "AAAfinancecommittee" or "password" are all examples of easily remembered passwords, more or less publicly knowable passwords. Less easily attacked passwords might be built from such a basic form, for instance, "smith12nov34street" or "AAAchairpersonSUE". These are slightly more secure, but being relatively easily predictable should not be relied upon to actually block unauthorized access. Effective access control requires passwords which are more difficult to guess or to find automatically, less publicly knowable (ideally not at all), and these are the subject of much of the rest of this article. One method of creating passwords that are memorable, but harder to attack successfully is to use selective substitution of numbers for letters, e.g. 'I' is replaced by '1', 'E' by '3' etc. This becomes even more secure if the numbers are 'shifted' on the keyboard. In this instance, the number '1' might be replaced by '!', assuming '!' is a permitted character in passwords on the relevant system.

In Conclusion :

When you think about a password, your mind will think a password is something secret, vital, important, private, or anything. Passwords are used all around the world, without password, everything will just be accessible and vulnerable. A password will be good IF the password doesn't come from a dictionary, a password which is "abcde" is easier to guess than "aBcDe", harder password would be "@B^&C(D*&E", if you can memorize hard passwords then your password would be harder to crack. A password is very different from ciphers. Cipher is an act of encrypting and decrypting stuffs. Read about ciphers on the next post.