Cryptography

What is Brute Force

In cryptanalysis, a brute force attack is a method of breaking a cryptographic system by trying a large number of possibilities using fast computers; for example, a large number of the possible keys in a key space in order to decrypt an encrypted message. The theoretical possibility of a brute force attack is recognized by the cryptographic system designers, they work to make the cryptographic system very improbable for computers to break using brute force attack. For that reason, one of the definitions of "breaking" a cryptographic scheme is to find a method faster than a brute force attack. The selection of an appropriate key length depends on how much it will be difficult to break it using a brute force attack. By obfuscating the data before encryption, brute force attacks are less effective and more difficult to determine. The brute force attack could be combined with a dictionary attack.

Cryptography

Cryptography (also known as cryptology; comes from Greek κρυπτός, kryptos, "hidden, secret"; and γράφω, gráphō, "I write", or -λογία, -logia, respectively)[1] is the practice and study of hiding information. It is sometimes called code, but this is not really a correct name. It is the science used to try to keep information secret and safe. Modern cryptography is a mix of mathematics, computer science, and electrical engineering. Cryptography is used in ATM (bank) cards, computer passwords, and shopping on the internet.

When a message is sent using cryptography, it is changed (or encrypted) before it is sent. The method of changing text is called a "code" or, more precisely, a "cipher". The changed text is called "ciphertext". The change makes the message hard to read. Someone who wants to read it must change it back (or decrypt it). How to change it back is a secret. Both the person that sends the message and the one that gets it should know the secret way to change it, but other people should not be able to. Studying the cyphertext to discover the secret is called "cryptanalysis" or "cracking" or sometimes "code breaking".

Different types of cryptography can be easier or harder to use and can hide the secret message better or worse. Ciphers use a "key" which is a secret that hides the secret messages. The cryptographic method needn't be secret. Various people can use the same method but different keys, so they cannot read each others' messages. Since the Caesar cipher has only as many keys as the number of letters in the alphabet, it is easily cracked by trying all the keys. Ciphers that allow billions of keys are cracked by more complex methods.

Caesar cipher

The Caesar cipher is a method of cryptography. It is named after Julius Caesar who used it to communicate with his army.
To make a message secret with the Caesar cipher, each letter in the message is changed using a simple rule: change by three. So each letter is replaced by the letter three letters ahead in the alphabet. A becomes D, B becomes E, and so on. For the last letters, we think of the alphabet as a circle and "wrap around." W becomes Z, X becomes A, Y becomes B, and Z becomes C. To change a message back, each letter is replaced by the one three before it. However it is possible to break Caeser Cipher easily using Microsoft Excel, so it may be better to use a more difficult code.

Changing by three is the rule that Julius Caesar used, but the same idea works for any number.
The Caesar cipher is a substitution cipher: each letter is replaced by another. No substitution cipher is really safe.

Password

A password is a way of authentication. It can be used as a means to identify a person. Since the password is the only way to identify a person, it has to be kept secret. A password can be static. This means it will remain the same unless the user changes it, or it rarely changes. Or a password can be dynamic. A dynamic password changes regularly and does not remain the same. One type of a dynamic password is a one-time pad that can only be used once.

Passwords were first used in the military. This was to be able to tell who was a friend and who was an enemy when it was dark.

Modern passwords are made of characters, letters and numbers. Sometimes a password will require a minimum number of characters. Usually this is from six to eight. Some websites allow only the use of letters and numbers, but no other characters on the keyboard. Other websites advise using a combination of letters and numbers to increase the "strength" of a password. Websites also advise changing a password once a year or more often to prevent hacking. A person may be able to guess a password if it is too easy. While being typed, each letter of a password is shown as * or •.

Other ways of verifying the identity of a person include using fingerprint scanners and face detection

Arabic , Urdu , Persian Alphabeds for hacking


The Arabic alphabet is an alphabet that has been used to write the Arabic language. Some other languages use a similar writing system; examples are Persian and Urdu.
There are 28 basic letters. All of them are cursive, both in handwriting and in print. This means that inside a word, a letter is usually directly connected to the letter following it. Arabic is written from right to left. Each letter can have up to 4 different forms. Which of the forms is used depends on the letters before and after it. The form for uppercase letters and lowercase letters is the same.
The alphabet can also be used to write numbers. This was common in the Middle Ages. Today it can be found more rarely. Usually, Latin-alphabet (Arabic) numbers are used.

Another usage that is rare today, is to use the letters of the alphabet to stand for numbers. That way, the letter ʼalif is 1, ب bāʼ is 2, ج ǧīm is 3, and so on until ي yāʼ = 10, ك kāf = 20, ل lām = 30, …, ر rāʼ = 200, …, غ ġayn = 1000. This is sometimes used to produce chronograms.