Unit 3-Symmetric Key Crypto_Part17

Unit 3-Symmetric Key Crypto_Part17 - The row index is given...

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DES Expansion Permutation - Example Unit 3 - 33 Input 32 bits Output 48 bits 1 1 0 1 1 0 0 0 0 1 0 0 1 1 0 1 1 0 0 1 1 1 1 1 0 1 1 0 0 0 1 1 31 0 1 2 3 4 3 4 5 6 7 8 7 8 9 10 11 12 11 12 13 14 15 16 15 16 17 18 19 20 19 20 21 22 23 24 23 24 25 26 27 28 27 28 29 30 31 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 1 1 0 1 1 1 1 0 0 0 0 0 0 1 0 0 1 0 1 1 0 1 1 1 1 0 0 1 1 1 1 1 1 1 0 1 0 1 1 0 0 0 0 0 1 1 1
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Unit 3 - 34 DES S-box The S-Boxes are the real source of the power (security) of DES. There are 8 different S-boxes Each S-box accepts 6-bits of input and produces 4-bits of output. An S-box has 16 columns and 4 rows where each element in the box is a 4-bit block.
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Unformatted text preview: The row index is given by bits 0 and 5 and the bits 1 to 4 supply the column index. The output of the S-Box is the value stored at the addressed row/column For example: Input 0 0 0 1 0 1 (6 bits) Output is 0 1 1 1 (4 bits) Column 2 Row 1...
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Unit 3-Symmetric Key Crypto_Part17 - The row index is given...

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