Introduction

Cryptoanalysis has existed since ancient times, it has long been a key part of warfare. Now it is more important than ever, as more and more information becomes encrypted whether simple or complex cryptography.

Types of CryptoAnalysis

Decipherment takes patience, you must attack with a logical approach to the patterns contained. To begin Decipherment you must firstly look at the structure of the encoded message and decide whether its numerical, alphabetical, polyalphabetical, alphanumerical or hyrogliphical. These are the basic forms or encrypted messages. Each type will encrypt its information in an entirely different way, some using substitution, some addition some may be algorithmic.

Numerical Encryption:
Usually either substituional such as 1 for A (except much more complex) or algorithmic, which uses a set mathematical formula (that rotates) to change the substitution used such as for the first letter 1 is A, for the second 1 is Z, for the third 1 is Y, etc... and this can be made so it skips large portions of the alphabet very quickly. It will usually have a key for the algorithm included at the beginning of the message so the authorized ciphering personnel know which algorithm to use.

Alphabetical Encryption:
The Simplest form of encryption and is easily broken by looking at looking at the patterns it revolves around elementary games where people scramble letters. for instance Z is A and A is Z etc... It can also be used with a skip letter pattern like a binary 1010010001 etc... pattern or a 101010101 etc.. pattern (1 being on, 0 being off)

Poly-Alphabetical:
An advanced form of encryption that isn't normally used except in automated computer encryption, here a capital and a normal letter may be different. For instance, someone may write "EmP" and actually mean "and" whereas "emp" may be nonsense like "fnd". Alot of bogus letters are usually introduced to throw the cipher off the track.

AlphaNumerical encryption:
Usually follows a displacement path, such as A0,L2,A4 which is 'and' but it could be encypted in many different ways to get the same letter, so it can seem like an infinetly complex message with no repeating patterns while it is actually one of the simplest.

Hyrogliphical:
Basically alphabetic substitution using graphical methods to try and conceal the message, in picture shows.

Conclusion

There are many different types of encryption and I have just covered the very basic ones. Unless you happen to have a PhD in Computer Mathematics (or Number Theory :P) and have been nominated for military crytographer, you won't be cracking modern encryption. But the simple encryption enemy clubs use if they don't have the right software can be broken by looking at these different types of encryption. Read the first few lines and look for common patterns then relate them to words and then to letters and finally you should be able to build up a message.

Good Luck on the Exam!

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