Table of Contents
Previous Section Next Section

Chapter 4: 0x400—Cryptology

Overview

Cryptology is defined as the study of cryptography or cryptanalysis. Cryptography is simply the process of communicating secretly through the use of ciphers, and cryptanalysis is the process of cracking or deciphering those aforementioned secret communications. Historically, cryptology has been of particular interest during wars: using secret codes to communicate with friendly troops while also trying to break the enemy's codes to infiltrate their communications.

The wartime applications still exist, but the use of cryptography in civilian life is becoming increasingly popular as more critical transactions occur over the Internet. Network sniffing occurs frequently enough that the paranoid assumption that someone is always sniffing network traffic might not be so paranoid. Passwords, credit card numbers, and other proprietary information can all be sniffed and stolen over unencrypted protocols. Encrypted communication protocols provide a solution to this lack of privacy and allow the Internet economy to function. Without SSL (Secure Sockets Layer) encryption, credit card transactions at popular websites would be either very inconvenient or insecure.

All of this private data is protected by cryptographic algorithms that are probably secure. Currently cryptosystems that can be proven to be secure are far too unwieldy for practical use, so in lieu of a mathematical proof of security, cryptosystems that are practically secure are used. This means that it's possible that shortcuts for defeating these ciphers exist, but no one's been able to actualize them yet. Of course, there are also cryptosystems that aren't secure at all. This could be due to the implementation, key size, or simply cryptanalytic weakness in the cipher itself. In 1997, under U.S. law, the maximum allowable key size for encryption in exported software was 40 bits. This limit on key size makes the corresponding cipher insecure, as shown by RSA Data Security and Ian Goldberg, a graduate student from U.C. Berkeley. RSA posted a challenge to decipher a message encrypted with a 40-bit key, and three and a half hours later, Ian had done just that. This was strong evidence that 40-bit keys aren't large enough for a secure cryptosystem.

Cryptology is relevant to hacking in a number of ways. At the purest level, the challenge of solving a puzzle is enticing to the curious. At a more nefarious level, the secret data protected by the aforementioned puzzle is perhaps even more alluring. Breaking or circumventing the cryptographic protections of secret data can provide a certain sense of satisfaction and certainly a sense of the protected data's contents. In addition, strong cryptography is useful in avoiding detection. Expensive network intrusion detection systems designed to sniff network traffic for attack signatures are useless if the attacker is using an encrypted communication channel. Often, the encrypted web access provided for customer security is used by attackers as a difficult-to-monitor attack vector.


Table of Contents
Previous Section Next Section