Unit 3-Symmetric Key Crypto_Part20

Unit 3-Symmetric Key Crypto_Part20 - DES Subkey Shifting...

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Unformatted text preview: DES Subkey - Shifting For rounds i=1,2,...,16 Let LK = (LK circular shift left by ri) Let RK = (RK circular shift left by ri) ri is 1 for rounds 1,2,9 and 16, and in all other rounds ri is 2 Unit 3 - 39 DES Subkey - Compression Each half key LK and RK is numbered 0,1,2,…,27 For rounds i=1,2,...,16 Left half of subkey Ki is the following bits of LK 13 22 16 18 10 11 23 3 0 25 4 7 2 15 27 6 14 26 5 19 20 12 9 1 Bits 8,17,21,24 of LK omitted each round Right half of subkey Ki is the following bits of RK 12 15 23 20 2 10 8 27 18 5 26 24 1 17 11 13 22 21 16 7 4 0 19 3 Bits 6,9,14,25 of RK omitted each round Unit 3 - 40 ...
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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_Part20 - DES Subkey Shifting...

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