Cracking Encrypted Systems By: Jason Schrecongost

Cryptography Derived from the Greek word “Kryptos” meaning “hidden” or “secret,” cryptography is the practice and study of hiding information. Cryptography is an ancient art dating as far back as 1900 B.C. when an Egyptian scribe used non-standard hieroglyphs Some argue that cryptography has been around ever since writing was invented.

Cryptography:Modern Cryptography in modern times, is a combination of both mathematics and computer science. Technology relies greatly on cryptography. For example: Credit Cards Computer Passwords eCommerce

Encryption By definition, encryption is any procedure used in cryptography to convert plaintext into cipher text in order to prevent any but the intended recipient from reading that data. The result is a cryptographic key. Encryption should be used when communicating over any untrusted medium.

Key A cryptographic key determines the output of an algorithm. The key is necessary to encrypt the plain text to cipher text, without it…the algorithm would produce no result.

Cipher A cipher is the algorithm used for encrypting and decrypting data. There are two main types of these algorithms. Symmetric Key Algorithms Asymmetric Key Algorithms

Symmetric Key Algorithms Symmetric Keys are a class of algorithms that use the same key for encryption and decryption Other names for this type include: Secret-Key Single-Key Shared-Key

Asymmetric Key Algorithms Also known as Public Key Cryptography, Asymmetric keys to encrypt a message differ from the key to decrypt it. This type of key contains both a private key and a public key Private Key-kept secret Public Key-can be distributed

Asymmetric Keys(Cont.) Of the two types of keys, this is the most common and more secure method. Bob must obtain Alice’s public key to decrypt her message.

Cracking Encryption Now that you have some what of an understanding of Encryption. You can better grasp on who to crack encryption keys. This is not an easy process but it can be done by certain methods.

Cracking Encryption This is just a chart showing the cost and time it takes for one to crack encryption keys As you can see, the higher the key bit is, the more time and money it takes to crack.

Brute Force! Because there is no real weakness is encrypted systems, Brute Force is necessary to crack the key. A Brute Force attack is an exhaustive search. It tries every possibility until it guesses the key. However, the bigger bit the key is the longer it takes to crack.

“Deep Crack” In 1998, Electronic Frontier Foundation built this $250,000 brute force cracking machine. It cracked a DES encryption key in less than 56 hours. DES uses a 56-bit key meaning there was 72 quadrillion possibilities.

Dictionary Attack A dictionary attack is just what it appears to be, it searches every word in the dictionary for a possible password to decrypt the cipher text. It may be easier and more effective to do a dictionary attack. But if a dictionary attack fails it may be necessary to use a brute force method.

Aircrack-ng Aircrack-ng is an excellent program for cracking encryption on wireless networks, usually in under ten minutes. It uses brute force to crack WEP keys and a dictionary attack to crack WPA keys. The program is available for both Windows and Linux and is available at: http://www.aircrack-ng.org/doku.php

Features

Aircrack-ng Demonstration Instead of explaining how this program works, it will be more beneficial to everyone to just see how it is done. http://www.youtube.com/watch?v=TiPWUykw3uU&NR=1

Conclusion Even though encryption is a very good way of securing data, the purpose of this presentation was to show you that with the right equipment it is possible to crack encrypted systems.

Sources http://en.wikipedia.org/wiki/Aircrack http://en.wikipedia.org/wiki/Asymmetric_key_algorithm http://www.tech-faq.com/dictionary-attack.shtml http://www.aircrack-ng.org/doku.php http://www.youtube.com/watch?v=TiPWUykw3uU&NR=1 http://en.wikipedia.org/wiki/Brute-force_search http://www.mycrypto.net/encryption/encryption_crack.html http://en.wikipedia.org/wiki/Brute_force_attack