---------------------------------------------------------------------- Paper title: Cryptography: An introduction Written by: Chroniccommand Written for: CodeShock Some credit to wikipedia. ---------------------------------------------------------------------- What is encryption Encryption is the technique of converting data from a plain text into what is called cipher text. Cipher text is information that has been encrypted using an algorithm or cipher into a character string. This data can be converted back into its original form or reverse the process is called decryption. To recover the original data that was once in plain text you need the decryption key, the decryption key will undo the process which encrypting the data has done. A decryption key is what determines the output of either the cipher or algorithm. --------------------------------\\\ History Cryptography in greek means: "hidden secret". Cryptography was originally created to encrypt secret data to protect unwanted eyes from seeing the original piece of text. This is still what encryption is mainly used for today. The development of digital computers and electronics after WWII made possible much more complex ciphers. Furthermore, computers allowed for the encryption of any kind of data representable in any binary format, unlike classical ciphers which only encrypted written language texts; this was new and significant. --------------------------------\\\ Types of encryption There are many types of encryption techniques. Here I will be going over: #DES #MD5 #NTLM #LM
DES: DES stands for Data Encryption Standard. It was selected by the NBS(National Bureau of Standards). In 1974 it was created by the IBM team. http://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Data_Encryption_Standard_InfoBox_Diagram.png/623px-Data_Encryption_Standard_InfoBox_Diagram.png MD5: MD5 stands for Message-Digest algorithm 5. MD5 has a 128-bit hash value. MD5 was designed by Ron Rivest in 1991 to replace an earlier hash function, MD4. In 1996, a flaw was found with the design of MD5. While it was not a clearly fatal weakness, cryptographers began recommending the use of other algorithms, such as SHA-1 http://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/MD5.svg/546px-MD5.svg.png NTLM: NTLM stands for NT Lan Manager. During protocol negotiation, the internal name is nt lm 0.12. The version number 0.12 has not been explained. It is the successor of LANMAN (Microsoft LAN Manager), an older Microsoft authentication protocol, and attempted to be backwards compatible with LANMAN. NTLM was followed by NTLMv2, at which time the original was renamed to NTLMv1. LM: LM stands for Lan Manger. LAN Manager hash is one of the formats that Microsoft LAN Manager and Microsoft Windows versions previous to Windows Vista use to store user passwords that are fewer than 15 characters long. This type of hash is the only type of encryption used in Microsoft LAN Manager (hence the name) and versions of Windows up to Windows Me. ----------------------------\\\ Cryptanalysis Cryptanalysis is the art of analyzing a cryptographic scheme. There are a wide variety of cryptanalytic attacks, and they can be classified in any of several ways. A common distinction turns on what an attacker knows and what capabilities are available. -----------------------------\\\ Cracking techniques There are some different types of cracking techniques I will discuss in the paper. First being brute force. Brute forcing is a strategy used to break the encryption of data. It involves traversing the search space of possible keys until the correct key is found. The selection of an appropriate key length depends on the practical feasibility of performing a brute force attack. By obfuscating the data to be encoded, brute force attacks are made less effective as it is more difficult to determine when one has succeeded in breaking the code.
Dictionary attack: A dictionary attack uses a brute-force technique of successively trying all the words in an exhaustive list (from a pre-arranged list of values). In contrast with a normal brute force attack, where a large proportion key space is searched systematically, a dictionary attack tries only those possibilities which are most likely to succeed, typically derived from a list of words in a dictionary. ----------------------------\\\ EOF -----------------------------\\\ I hope this paper provided more insight on cryptography and encryption. Please PM me or reply if you have any questions/comments.