Unit 3-Symmetric Key Crypto_Part28

Unit 3-Symmetric Key Crypto_Part28 - a 2,3 a 3,0 a 3,1 a...

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Unit 3 - 55 Initial Step The process begins by grouping the plaintext bits into a column array by bytes. The first four bytes form the first column; the second four bytes form the second column, and so on. If the block size is 128 bits then this becomes a 4x4 array. For larger block sizes the array has additional columns. The key is also grouped into an array using the same process. a 0,0 a 1,0 a 2,0 a 3,0 a 0,1 a 1,1 a 2,1 a 3,1 a 0,2 a 1,2 a 2,2 a 3,2 a 0,3 a 1,3 a 2,3 a 3,3 a 0,0 a 0,1 a 0,2 a 0,3 a 1,0 a 1,1 a 1,2 a 1,3 a 2,0 a 2,1 a 2,2
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Unformatted text preview: a 2,3 a 3,0 a 3,1 a 3,2 a 3,3 Unit 3 - 56 AES ByteSub The substitution layer uses a single S-box (rather than the 8 S-boxes used in DES). The Rijndael S-box is a 16 x 16 array Each element in the current column array serves as an address into the S-box where the first four bits identify the S-box row and the last 4 bits identify the S-box column. The S-box element at that location replaces the current column array element....
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This note was uploaded on 03/17/2011 for the course ECE 4472 taught by Professor Ouda during the Fall '10 term at UWO.

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Unit 3-Symmetric Key Crypto_Part28 - a 2,3 a 3,0 a 3,1 a...

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