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Cryptorgraphy: Advanced Encryption StandardAdvanced Encryption Standard is a block cipher that has been adopted as an encryption standard by the US Government. It is soon expected to be used world wide. With time it will also be rigorously analyzed as DES has been. AES was adopted by NIST in November of 01, after AES went through a standardization process for 5 years. Originally AES was written by two cryptographers from Belgium; Joan Daemen and Vincent Rijmen. AES was actually based on their previous design called “Square” or “Rijndael”. AES is not exactly the same as Rijndael, since it actually support larger range of block and key sizes. AES on the other hand, has only a block size of 128 bits and key sizes of 128, 192, and 256. In this paper I will look as close as I can at what AES is and how it works. I will also look at it in terms of how it was tested for security in terms of possible attacks that can be launched at it. I will also define the terminology used with descriptions of AES. It is important to understand what is meant by block cipher before continuing. Essentially, block cipher is a type of symmetric key cipher. This key cipher operates on groups of bits of fixed length which are called blocks. Usually these block sizes are 64 to 128 bits, but they can be many different lengths. When a message is longer than the block size one of mode operations are used. These operations are used to encrypt the context. Typically, mode operations have different types of properties in respect to error proportion and different types of vulnerability attacks. |